Unable to link my NNID to any Nintendo Account. : r/3DS

Nintendo Support: Nintendo Account FAQ

Nintendo Account, Support

How to create and link a Nintendo account for Nintendo Switch (2022)

PSA: When claiming your User ID for a Nintendo Account, you know you've done it correctly if you see this grey bar when you login. : r/NintendoSwitch

Nintendo Switch Account Hack Affected 300,000 Users

How to permanently delete your Nintendo account

All the Nintendo accounts you need for your Switch - Polygon

Nintendo wants a “smooth transition” to their next-gen console through Nintendo Accounts - Meristation

How to Gameshare Between Accounts on Nintendo Switch - Nintendo Supply

How do I link my mobile Sky account to my Nintendo Switch account? — Sky Beta Help Center