EDIT:
So according to this thread, this is a Google related change and not Nvidia?
In which case, similar to the banner issue from a previous update, you can get a different launcher (see comments for FLauncher) to avoid it
https://www.reddit.com/r/ShieldAndroidTV/comments/181vh4t/ads_at_full_screen/
To my knowledge no but it wouldn’t surprise me if someone found a way to do it. It’s just that chromecast/Google TVs is a lot more friendly and open. You can cast iOS or android.