Nutella is a proper noun and also a loanword, I was expecting native common noun pairs. (Btw the issue exists in French too for this word, and a few others like Wifi or Gameboy)

Actually you can't really say this: https://german.stackexchange.com/questions/8527/wer-sagt-die... See the map in this thread.

It's basically different in any county and different counties can be right next to each other.