If you can't move Mouse in NVIDIA GeForce Experience Overlay, use Borderless window and see. More suggestions are here in this post.

How to Open Nvidia GeForce Experience Overlay? GeForce Experience in-game overlay enables you to access GPU-accelerated video recording, screen-shot capture, broadcasting, and cooperative gameplay ...

The Nvidia app is out of beta and aims to improve the old GeForce Experience with interface changes and a bulked-up in-game overlay.

Why doesn’t NVIDIA Performance Overlay work? If the NVIDIA GeForce Experience overlay feature is not working on your PC, the problem is likely to be caused due to outdated or faulty drivers.