For what it is worth, when I hear "Six Nations", I think "Iroquois Confederacy".

And as parochial as you think that American sports are, the USA has a population that is half again as big as the "Six Nations" that you intended. And here is an important fact. Most people in the world who speak English as their first language, live in the USA. The dominance of American perspectives in online conversations in English reflects our actual representation among native English speakers.