To get NVIDIA Image Scaling to work, you have to enable it. There are two ways to enable NVIDIA Image Scaling, via the NVIDIA Control Panel and via the GeForce Experience. If you do not find an option to enable NVIDIA Image Scaling in GeForce Experience, enable the Experimental features option in GeForce Experience. After that, a new version of the app will be downloaded automatically. Now, restart the GeForce Experience app and you will see the option to enable NIS there.