It means "Never In My Life." A way of stating that you would never want to do the topic being discussed. Created by Luis, Mikey, Shane, and Devin in California. It is commonly used in exaggeration.
Nhial the type of guy to steal your girl. He usally is 6ft 5 and has hops, he is a beast basketball player, you would not like to get in a fight with him as he will knock the shit out of you.