Nah in most cultures means "No". In my culture, it means an assuring "Here, take it from me". Only family and close friends use it with each other. With a change of tone, it could also mean a dismissive "Take that, sucker!" to a rude person. So.
#INTJ ..... when someone I don't fuck with talks to me about anything! The whole conversation is defaulted to ZERO interest. Proceed with preprogrammed laughs & replies while simultaneously retreating to inside your head.