NexGen Energy : Exploration Update and Commencement of 2022 Regional Program

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NexGen 2021 Drilling Assay Results Confirm Uranium Mineralization Below Arrow At

Depth and Commencement of 2022 Regional Exploration Program

Vancouver, BC, July 28, 2022 - NexGen Energy Ltd. ("NexGen" or the "Company") (TSX: NXE) (NYSE:

NXE) (ASX: NXG) is pleased to announce drill assays from 2021 confirm discovery of a uranium mineralized zone below the known Arrow Deposit and at Camp East:

• Below Arrow - multiple intersections of uranium mineralization were made significantly below Arrow, including 0.10% U3O8 over 7.0 m in AR-21-268 from 1128 m to 1135 m down hole;
• Camp East - uranium concentration of 0.10% U3O8 in RK-21-140 from 166 m to 167 m down hole in association with brittle structure and hydrothermal alteration.

Further, NexGen has commenced 2022 drilling focused on regional exploration targets at the 100% owned Rook I project (the "Project"); and an extensive geophysical program over high priority areas of NexGen's mineral tenure in the southwest Athabasca Basin, Saskatchewan.

Leigh Curyer, Chief Executive Officer, commented: "The intersection of mineralization below the known Arrow Deposit and along trend at Camp East highlights the extent and potential for additional significant discoveries at Rook I. The geology team led by Grant Greenwood are well positioned for the 2022 drilling season which incorporates an extensive regional geophysical survey as a foundation for drilling in 2023 and beyond."

Grant Greenwood, Vice President, Exploration, commented: "The 2021 exploration drilling successfully intersected uranium mineralization. In addition to mineralization, these encouraging 2021 exploration results share alteration and structural similarities to those intersected in the discovery hole at Arrow (AR- 14-01 or RK-14-21). NexGen is poised to advance high priority targets on the Rook I property in a systematic fashion from Arrow proximal outwards. The geophysical survey plans are strategic initiatives in developing highly prospective conductors in greenfield areas of the well situated NexGen mineral tenure in the emerging southwest Athabasca Basin uranium district."

2022 Drilling

The Rook I project - home to the Arrow Deposit - hosts numerous, underexplored electromagnetic conductors (conductors) and structural corridors. While development of the Arrow Deposit is progressing optimally, NexGen's 2022 exploration program will focus on these underexplored targets towards making additional material discoveries. The program will target high priority areas (Figure 1) and build off the positive 2021 drilling results that intersected brittle structural disturbance and hydrothermal alteration on multiple conductors.

This drill program - testing six (6) conductive trends - is designed to evaluate prospective targets systematically with aggressive step-outs along high priority conductors.

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Drilling targets areas (from West to East):

• Patterson Corridor (PLC) - Systematic testing along trend of Arrow, as well as at Camp East where 2021 drilling intersected anomalous radioactivity. This fertile trend has a strike length of approximately 9 km on the Rook I property and remains highly prospective for further investigation.
• Mirror - Testing location with conductive response variation along the edge of a gravity low. The Mirror conductor is parallel immediately to the east of the Arrow conductor and of high priority.
• PLC East - Tests of segmented conductive responses on edges of gravity lows. PLC East is located proximal to the Arrow conductor with similar geometry.
• Derkson West - Follow-up of positive results from 2021 by testing along strike in both directions. Similar geometry to the PLC with a northeast-southwest trending conductor along magnetic gradient, coincident with local gravity lows.
• Derkson - Systematic drilling along prospective conductors in gravity lows. This high priority portion of the Derkson corridor for testing in 2022 contains discrete and strong conductive responses with interpreted structural disruptions.
• Derkson East - Targeting significant flexure of an underexplored conductor within a gravity low interpreted as localized structural disruption.

All target areas exhibit similar geophysical characteristics to Arrow, including strong conductive signatures with numerous off-sets coincident with discrete gravity lows and steep magnetic gradients. Structural interpretations across the property indicate several conductors lie along significant rheological/lithological contrasts interpreted to possess structural conditions favourable for localized uranium mineralization. Additionally, analysis of previous drilling has also revealed several target areas containing prospective alteration and geochemical signatures indicative of uranium bearing systems. The 2022 summer program incorporates 3 rigs for 12,000 meters in total.

These prospective signatures are present within the 2021 Exploration drilling results, in which 18 holes were completed for a total of 10,849.04 m (Figure 2). The program tested prospective electromagnetic conductors near Arrow with 6,400.31 m and a further 4,448.73 m tested significantly below the current outline of the Arrow Deposit resource (Figure 3). Brittle structural disturbance and hydrothermal alteration were intersected in all targeted areas, including anomalous uranium concentration below Arrow in drill hole AR-21-266 and -268, and at Camp East in drill hole RK-21-140 (see assay results in Table 1).

Strategic Geophysics

Covering prospective conductive trends on NexGen's SW1, SW2, and SW3 properties in the southwest Athabasca Basin (Figure 4), this extensive geophysical program is designed to gain further resolution on conductors and identify stacked geophysical anomalies for greenfields exploration drilling.

SW1 (Figure 5) - Ground electromagnetic survey along approximately 9 km conductor to further refine prospective targets for follow-up drilling.

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Continuity of the conductor suggests a well-developed structural trend with several breaks and jogs. The ground electromagnetic survey is designed to focus high-resolution geophysical data over these prospective features of the SW1 property and highlight specific areas for follow-up drilling.

SW2 (Figure 6) - Ground gravity survey to generate and prioritize targets by identifying stacked anomalies.

Through historic magnetic and electromagnetic surveys, the SW2 property is highlighted by numerous broad prospective trends. The addition of a ground gravity survey in the central portion of the property is planned for focussing exploration attention to specific locations along these trends where geophysical anomalies align for follow-up drilling.

SW3 (Figure 7) - Ground IP/Resistivity survey to generate and prioritize targets along approximately 6 km of prospective conductor that straddles the Athabasca Basin boundary, south of Cameco's Centennial Deposit.

This ground IP/resistivity is designed to provide resolution over this ideally situated conductor at the edge of the Athabasca Basin to optimize future drilling and advance the SW3 property towards discovery.

Figure 1: 2022 Exploration Target Areas

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Figure 2: 2021 Exploration Drilling

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Figure 3: 2021 Below Arrow Exploration - Drill holes Completed - Plan View (left)

and Cross Section looking Northeast (right)