One thing I seen in the images for Nigrum is that the new buds are colored dark grey to black, same color like when JM die back. I think there was one picture on the link I posted above.I will get some pictures of the tree as a whole and the bark sometime today.
The Big Tooth maple, Acer grandidetatum, is a western tree. I'm not sure if it grows in NC but I doubt it is naturalized there.Looks like a big tooth maple for sure
I concur.Looks a bit like a hedge maple, Acer campestre.