So basically what I've gathered from the reddit forums and angry old men is that Nu Metal can be defined as "generally characterized as having downtuned guitars, sometimes 7-string guitars, little to no guitar soloing, and influences from other music genres, usually rap and industrial" i don't really think that helps. And also I think it's more a feeling...which isn't true because it's actually a genre. But probably like the super angsty lyrics, and good music.