I’ve copied the setup I was using on my Raspberry PI over to my new Nvidia Shield TV and I’m very satisfied with the result, so I wanted to share it. This is by far the best media center experience I’ve had so far - those of you considering buying new hardware for Retroarch should really consider it as an option.
A video of the setup:
There are links to various configs and apps in the video description, if you want to reuse some of it.
Thank you Retroarch team for making this possible!