Something I've noticed. If your NES controller isn't working with Homebrew apps - Try a different Wii-mote! - Didn't work AT ALL with my official blue one, with this one it's perfect! :
How to Play NES Games on Wii U FREE (FCE Ultra GX Tutorial 2023) - YouTube
Alter Ego (Homebrew) (Nintendo NES) – J2Games
30+ Great Emulators You Can Run on Your Nintendo Wii
Multidude - NES Homebrew Game - Stone Age Gamer
How to play the Nintendo (NES) rom games on the Wii with boxart in WiiFlow (Sub request video) - YouTube