Tamriel is "fantasy" world and all races is "fantasy" races , but Bretons sound like you talking about people from Ireland and United Kingdom, and also i heard there is ethnic group in United Kingdom and France called "Breton people"

And Nords sounds like you talking about real life people from "Nordic countries" and their associated territories, like the Faroe Islands, Greenland and ?land.

I mean if some one talking about bretons and nords from TES, people who have no clue about TES games can take as some one talking about Breton people from UK and France, and when some one talking about Nords people can take it as some one talking about people from places like Iceland and Faroe Islands.

I mean many ppl hate fantasy nord race from Skyrim(some many of their npcs is racists, and other npcs making racistic dialogues if you playing dark elf or khajit, and also screaming "Skyrim For Nords" when trying to kill you or other npcs which sounds like all races expect nords should get killed or get out.

But im very sure that no one of people who hates nords from Skyrim hates people from Nordic countries(Same goes for Bretons).