You're right although Loire-Atlantique and the Vendee are part of the Pays de la Loire.
It definitely isn't in Brittany.
I don't know where people are getting the nonce pronounciation as it is Nunt or Narnt.
Nantes is in the Vendee, unlike Rennes, which is Breton.
We drive through Nantes to get to our holiday destination. One of the easier peripheriques to negotiate.