I like the University of North Dakota Mighty Norse. It has a better ring to it than Fighting Norse. I think The University of North Dakota Northern Warriors has a lot of "North" in the name. The mascot could be named Gunnarr.
GUNNARR: Old Norse name composed of the elements gunnr "battle, fight" and arr "army, war," hence "soldier, warrior." In mythology, this is the name of the husband of Brynhildr.