I would say a few things...
First, I'm not sure that Chug = Nu.
Second, how many songs does Nevermore have based on Chug? If you've listened to
Dreaming and came away thinking "Nu Metal", than I don't know what to say. I think the ultra crisp sound of
Dead Heart shares some common ground with Nu Metal, but that ground doesn't overlap that all that widely.
Third, I have no intrinsic issue with Nu Metal, other than the overall quality of the genre. I totally love me some Lamb of God, early KSE, Trivium and Disturbed. Not sure what of that's Nu and what's not. Hard to keep track.
Finally, if Nevermore is in fact Nu Metal, than that raises that status of the Nu Metal genre, and officially makes Doom Metal's worst genre.