Doing some character analysis of Nick for an upcoming chapter and it's becoming clearer to me that teen Nick is violent fundamentally because he's emotionally neglected.
He doesn't know what emotional regulation looks like because his parents never really bothered to teach him - they, as image-conscious careerists, just acted regulated and expected him to echo.
His feelings were generally minimized because it was easier than dealing with them. He was rarely told no; when he got in trouble, it was rarely with consequences, and when he hurt people, his parents covered for him for the sake of his success and image.
Anger, contempt, etc. went unchecked and when they inevitably exposed him to fights (and even crime), those were 'dealt with' rather than addressed (and Nick learned to hide these well, not that he really needed to).
Basically, all of this creates a kind of gleeful social detachment, low fear response (to consequences and authority in general), and dominance-seeking that his home-life never bothered trying to contain.
TLDR; Nick learned how to be a sobbing crying SIMP for Hayko from all his nannies and chauffeurs, not his parents.
