To turn on overlays on the NVIDIA App, please press the triangle button (located top right next to the Send Feedback/Bubble & Log In/Profile button). Alternatively, you can press the Alt + Z on your keyboard to open & close the overlay.
Note that the new NVIDIA app overlay has a different look than the GeForce Experience overlay. The new overlay menus/options are located on the side of the screen with the rest of the screen clear of obstruction, while the old overlay options are located on the center of the screen and dims the rest of the screen.
Any options regarding the overlay (such as recording, shortcut, heads-on display) can be accessed by opening the overlay and pressing the cogwheel button on the top right of the overlay.
If you want to turn off the overlay permanently, you can go to Settings > Features > Overlay > NVIDIA Overlay, and turn off overlays by pressing on the green slider.
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