Unless hugely outnumbered, I think the military edge was clearly with the Vikings.
I doubt there was much of an edge for the Vikings -- bow and arrows, and spears, differed little from 'skraelings' to Vikings. The Vikings had metal weapons and perhaps armor, but I suspect that to economize, the amount of armor among colonizers was much lower than it was among the population back home. Also, they were likely greatly inferior in numbers, give or take nutjobs like the daughter of Eric the Red, who killed half the women on one expedition, doing it while they slept.
Remember that most Indian tribes were pushed here when the Steppe people of Central Asia expanded. Think of the Mongol hordes or the Scithians.
They could fight among themselves and often did. Not sure when the Iroquois Nation was founded but one of the reason was that the wars devastated the population.
The Viking may have had an advantage in war but a great Indian general could have defeated them, if the Indians had united.