Went to update the Switch and since the firmware update itself was already downloaded and pre-installed, all I had to do was just press A & restart. Afterwards, the Pokkén controller became automatically usable on the Switch. It's true that one can enjoy using the Pokkén controller to play Mario Kart you have to remember that the L and R shoulder buttons aren't on the top but rather at the bottom nearby Start & Select so this is something that screws up with one's mind. Now I have three Switch controllers. Joy-Cons (suppose you could count it as 2 controllers) + Pro Controller + Pokkén Controller.