On paper the 1060 is very slightly better, in real gaming performance they are closely matched with some games preferring AMD and some games preferring Nvidia it's tough to say.
However there is somewhat of a pattern in that DX12 games run slightly better on the 480, while generally games that run DX11 prefer the 1060. And of course there are always games like Assassin's Creed which always prefer Nvidia.
So it's really a tradeoff. I say whichever one you can get for cheaper and if you find a model you like.