I've seen youtube vids of people playing WiiU on the Shield though, with Launchbox and Retroarch?
https://www.reddit.com/r/ShadowPC/comments/c4k1p5/the_best_gaming_experience_on_shield_tv_shadow_pc/
I know CEMU works on PC for Wii U games, but is the Nvidia Shield powerful enough to handle CEMU/Launchbox to run Wii U games?
Namely Breath of the Wild.