Can I Use an Apple account to Link My Nintendo Account on the Nintendo Switch?
Although you can create a Nintendo Account with an Apple account, your Apple account is not currently a sign-in option on the Nintendo Switch system. Please use a different log in method (e-mail address, Facebook, Google, or Twitter) to link your Nintendo Account to your user profile on Nintendo Switch.
If you have created a Nintendo Account with an Apple account only, please log into your from a computer or smart device and register an email address or link an additional service.