In the sense that they saw nature as animated by invisible spirits, yes, the Norse, and the Greeks too were animists. In the tale of the death of Balder, everything on land in the water and in the air has to swear never to harm Balder - so obviously, all these things must have been seen as having not only some awareness but volition too. Of course, Mistletoe was the thing that didn't take the vow, as it grows on other trees, and hence Balder was killed with a spear of mistletoe. The Greeks too believed in nature spirits, nymphs and so on. So did the Celts.
belief in nature spirits doesnt equate to animist. But yes, they were...but more so in their indo-european origins.
