NexGen Announces Best Hole to Date (RK-24-222) and High-Grade Expansion at Patterson Corridor East Concluding a Successful 2024 Drilling Program

• NexGen's 2024 exploration campaign delivered a new discovery on Rook I at Patterson Corridor East ("PCE") 3.5km east of Arrow.
• Subsequent drilling has materially expanded the mineralized zone to 600 m strike length and 600 m vertical extent with 19 of 30 holes intersecting mineralization including 10 holes with multiple intervals >10,000 cps.
• Today's announcement highlights the best hole to date at PCE (RK-24-222) returns 17.0 m wide vein with multiple high intensity (>61,000 cps) occurrences.
• In 2024, PCE is the largest drill program in the Athabasca Basin by any Company at 34,000 meters (m).

VANCOUVER, BC, Nov. 12, 2024 /PRNewswire/ - NexGen Energy Ltd. ("NexGen" or the "Company") (TSX: NXE) (NYSE: NXE) (ASX: NXG) is proud to announce the completion of its 2024 drilling campaign at Patterson Corridor East (PCE) that included more than 34,000 m across a total of 46 drillholes. Upon initial discovery of intense uranium mineralization at PCE (see March 11 News Release), the Company directed all drilling activity to focus exclusively on PCE, whereby 19 of 30 holes intersected mineralization. Bold and systematic spacing of drillhole intercepts have quickly grown the discovery from a single hole to a broad and continuous new uranium discovery. Real-time evaluation of results throughout the duration of the program focused on determining the overall outer extents of the mineralized zone and in parallel, precisely targeting high-grade sub-domains (Figures 1 and 2, Table 1).

In late October, a high-grade portion has presented itself within the overall mineralized zone with upgraded intensity of mineralization in the now best hole to date, RK-24-222 (Figure 3). A 17.0 m wide vein with multiple occurrences of off-scale (>61,000 cps) mineralization (Table1, Figure 3). In addition, RK-24-220 and -223 intersected strong mineralization up to 41,000 cps and 40,000 cps, respectively including multiple intercepts of >10,000 cps. System strength is confirmed by these zones characterized by semi-massive to massive replacement by uraninite. A high-grade sub-domain of the mineralized footprint now covers 100 m of strike and 170 m of depth extent with potential growth in all directions (Figure 2). The high-grade intersection in RK-24-222 represents the fifth drillhole at PCE to return off-scale (>61,000 cps) mineralization, joining previous significant intersections in RK-24-183, -197, -202, and -207.

Leigh Curyer, Chief Executive Officer, commented: "This focused effort has elevated the materiality of PCE and today's results highlight the increasing potential of the PCE system with RK-24-222. With 600 m of strike length and 600 m of depth extent, this new zone located entirely within competent basement rock only 3.5 km from the flagship world-class Arrow deposit has emerged as a compelling and prospective addition to NexGen's dominant portfolio in the south western section of the Athabasca Basin.

NexGen's disciplined dual focus on the advancement of the Rook I Project and the expanded exploration at PCE demonstrates the Company's commitment to unlocking the full potential of this major uranium district at a time where the need for clean affordable safe baseload energy has never been more evident. With the world's leading tech companies all committing to nuclear power in recent month's the outlook is incredibly exciting in the nuclear fuel space."

Assays from disclosed intersections are expected in Q4 2024 and Q1 2025, with reporting to follow. Exploration activity will resume in January 2025 with planning underway for a significant drill program at PCE where the prospectivity for material growth is clearly evident.

Table 1: 2024 Spectrometer results since previous release on August 8, 2024

• All depths and intervals are meters downhole, true thicknesses are yet to be determined.
• "Off-scale" refers to >61,000 cps total readings by gamma spectrometer type RS-125.
• Unconformity of 'N/A' denotes a lack of visible contact between Athabasca sandstone and basement rock.
• Maximum internal dilution 2.0 m downhole.
• Minimum thickness of 0.5 m downhole.
• All depths and intervals are metres downhole, true thicknesses are yet to be determined. Resource modelling in conjunction with an updated mineral resource estimate is required before true thicknesses can be determined.

About NexGen

NexGen Energy is a Canadian company focused on delivering clean energy fuel for the future. The Company's flagship Rook I Project is being optimally developed into the largest low cost producing uranium mine globally, incorporating the most elite standards in environmental and social governance. The Rook I Project is supported by a NI 43-101 compliant Feasibility Study which outlines the elite environmental performance and industry leading economics. NexGen is led by a team of experienced uranium and mining industry professionals with expertise across the entire mining life cycle, including exploration, financing, project engineering and construction, operations, and closure. NexGen is leveraging its proven experience to deliver a Project that leads the entire mining industry socially, technically, and environmentally. The Project and prospective portfolio in northern Saskatchewan will provide generational long-term economic, environmental, and social benefits for Saskatchewan, Canada, and the world.

NexGen is listed on the Toronto Stock Exchange, the New York Stock Exchange under the ticker symbol "NXE" and on the Australian Securities Exchange under the ticker symbol "NXG" providing access to global investors to participate in NexGen's mission of solving three major global challenges in decarbonization, energy security and access to power. The Company is headquartered in Vancouver, British Columbia, with its primary operations office in Saskatoon, Saskatchewan.

www.nexgenenergy.ca

Technical Disclosure*

All technical information in this news release has been reviewed and approved by Jason Craven, NexGen's Manager, Exploration, a qualified person under National Instrument 43-101.

Natural gamma radiation in drill core reported in this news release was measured in counts per second (cps) using a Radiation Solutions Inc. RS-125 gamma spectrometer. The reader is cautioned that total count gamma readings may not be directly or uniformly related to uranium grades of the rock sample measured; they should be used only as a preliminary indication of the presence of radioactive minerals.

A technical report in respect of the FS is filed on SEDAR ( www.sedar.com ) and EDGAR (www.sec.gov/edgar.shtml ) and is available for review on NexGen Energy's website (www.nexgenenergy.ca ).

Cautionary Note to U.S. Investors

This news release includes Mineral Reserves and Mineral Resources classification terms that comply with reporting standards in Canada and the Mineral Reserves and the Mineral Resources estimates are made in accordance with NI 43-101. NI 43-101 is a rule developed by the Canadian Securities Administrators that establishes standards for all public disclosure an issuer makes of scientific and technical information concerning mineral projects. These standards differ from the requirements of the Securities and Exchange Commission ("SEC") set by the SEC's rules that are applicable to domestic United States reporting companies. Consequently, Mineral Reserves and Mineral Resources information included in this news release is not comparable to similar information that would generally be disclosed by domestic U.S. reporting companies subject to the reporting and disclosure requirements of the SEC Accordingly, information concerning mineral deposits set forth herein may not be comparable with information made public by companies that report in accordance with U.S. standards.

Forward-Looking Information

The information contained herein contains "forward-looking statements" within the meaning of applicable United States securities laws and regulations and "forward-looking information" within the meaning of applicable Canadian securities legislation. "Forward-looking information" includes, but is not limited to, statements with respect to mineral reserve and mineral resource estimates, the 2021 Arrow Deposit, Rook I Project and estimates of uranium production, grade and long-term average uranium prices, anticipated effects of completed drill results on the Rook I Project, planned work programs, completion of further site investigations and engineering work to support basic engineering of the project and expected outcomes. Generally, but not always, forward-looking information and statements can be identified by the use of words such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or "believes" or the negative connotation thereof or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might" or "will be taken", "occur" or "be achieved" or the negative connotation thereof. Statements relating to "mineral resources" are deemed to be forward-looking information, as they involve the implied assessment that, based on certain estimates and assumptions, the mineral resources described can be profitably produced in the future.

Forward-looking information and statements are based on the then current expectations, beliefs, assumptions, estimates and forecasts about NexGen's business and the industry and markets in which it operates. Forward-looking information and statements are made based upon numerous assumptions, including among others, that the mineral reserve and resources estimates and the key assumptions and parameters on which such estimates are based are as set out in this news release and the technical report for the property , the results of planned exploration activities are as anticipated, the price and market supply of uranium, the cost of planned exploration activities, that financing will be available if and when needed and on reasonable terms, that third party contractors, equipment, supplies and governmental and other approvals required to conduct NexGen's planned exploration activities will be available on reasonable terms and in a timely manner and that general business and economic conditions will not change in a material adverse manner. Although the assumptions made by the Company in providing forward looking information or making forward looking statements are considered reasonable by management at the time, there can be no assurance that such assumptions will prove to be accurate in the future.

Forward-looking information and statements also involve known and unknown risks and uncertainties and other factors, which may cause actual results, performances and achievements of NexGen to differ materially from any projections of results, performances and achievements of NexGen expressed or implied by such forward-looking information or statements, including, among others, the existence of negative operating cash flow and dependence on third party financing, uncertainty of the availability of additional financing, the risk that pending assay results will not confirm previously announced preliminary results, conclusions of economic valuations, the risk that actual results of exploration activities will be different than anticipated, the cost of labour, equipment or materials will increase more than expected, that the future price of uranium will decline or otherwise not rise to an economic level, the appeal of alternate sources of energy to uranium-produced energy, that the Canadian dollar will strengthen against the U.S. dollar, that mineral resources and reserves are not as estimated, that actual costs or actual results of reclamation activities are greater than expected, that changes in project parameters and plans continue to be refined and may result in increased costs, of unexpected variations in mineral resources and reserves, grade or recovery rates or other risks generally associated with mining, unanticipated delays in obtaining governmental, regulatory or First Nations approvals, risks related to First Nations title and consultation, reliance upon key management and other personnel, deficiencies in the Company's title to its properties, uninsurable risks, failure to manage conflicts of interest, failure to obtain or maintain required permits and licences, risks related to changes in laws, regulations, policy and public perception, as well as those factors or other risks as more fully described in NexGen's Annual Information Form dated March 6, 2024 filed with the securities commissions of all of the provinces of Canada except Quebec and in NexGen's 40-F filed with the United States Securities and Exchange Commission, which are available on SEDAR at www.sedar.com and Edgar at www.sec.gov .

Although the Company has attempted to identify important factors that could cause actual results to differ materially from those contained in the forward-looking information or statements or implied by forward-looking information or statements, there may be other factors that cause results not to be as anticipated, estimated or intended. Readers are cautioned not to place undue reliance on forward-looking information or statements due to the inherent uncertainty thereof.

There can be no assurance that forward-looking information and statements will prove to be accurate, as actual results and future events could differ materially from those anticipated, estimated or intended. Accordingly, readers should not place undue reliance on forward-looking statements or information. The Company undertakes no obligation to update or reissue forward-looking information as a result of new information or events except as required by applicable securities laws.

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SOURCE NexGen Energy Ltd.