What, exactly, is the difficulty?
The Norse Vikings are, like Native Americans, an aboriginal people. The Norse people are largely a remnant of ‘Old Europe’, the prehistoric inhabitants descending directly from early Homo sapiens, the Cro-Magnon people. (The prevalence of yDNA haplogroup I among the Norse descends from the DNA of Cro-Magnon people.)
The later invasions by the Indo-Europeans only partially influenced the remote Norse regions, mainly because the rugged near arctic environment was hostile to farming, the Indo-European agricultural cultures. To a significant degree, the Norse remained a hunter-gather culture subsisting on fishing and forest hunting.
The spiritual traditions of the remote Norse regions remain animistic, with nature spirits, a giant ‘thunder bird’ responsible for arctic blizzard storms, and female shamans who maintained constructive relationships with nature spirits, especially Elves and Giants. Even shapeshifters. Norse aborigines and Native American aborigines have a surprising degree of spirituality in common.
To this day, even under the influence of southern Hellenism and later Christian spiritual traditions, Scandinavians maintain a profound reverence for the spirituality of nature.