The only way I can think of is to connect it to your pc and use hid to vpad.https://gbatemp.net/threads/hid-to-vpad.424127/I recently purchased the SNES online controller for my switch and I wondered if there was anyway through homebrew that I could connect it to my Wii U for games like Mario Maker?
Is that their magicNS adapter? I've got that one but I don't know if it for a fact supports the snes online controllers?it's probably possible, yes. I know that both the snes and nes nso controllers can connect to the pc without any additional hardware. however, the wii u either needs the toshiba bluetooth stack (this really messed up my other bluetooth devices) or the mayflash adapter (very much recommended). the mayflash adapter even works now that my bluetooth has gone out.
You could use the ones from the Snes mini classic.