According to this thread on the Nintendont Github, there are some versions of Nintendont that have issues with GC WiiU adapters. I've also heard about some 3rd party adapters being problematic as well. I'd try the suggested version from this...
Are you leaving it in PC mode when using it with Nintendon't? If so, that's likely your issue. Switch to WiiU/Switch mode and reboot your console and you should be good to go.
Are you using an official adapter, the Mayflash, or another generic/3rd-party? If you're using Mayflash, are you in WiiU/Switch mode or PC mode?
What kind of controller are you using? Official, Smash, old (<2012) 3rd party, or new 3rd party?
Make sure you have both USB ports plugged in. Black is for controller power and data, gray is for controller rumble power.
If you're using a USB hub, try a different one that is powered separately from the WiiU
I recently installed a bunch of WiiU VC injects with UWUVCI: https://gbatemp.net/threads/release-uwuvci-injectiine.486781/
They show on the WiiU menu instead of the Wii menu.
Otherwise, you're likely best off using a USB loader and making...
hahahaha I'm half way through a bag off my Volcano and my tolerance is way down because I haven't been smoking much lately, so I was a little slow to catch that that was what your angle was