You landed a solid kick to Nick's jaw, sending him flying back.

You and Nick were having a fire fight, each of your bullets colliding in midair.

Nick's eyes were blood red as he threw a fireball directly at your face.

Nick kicked the knife out of your hand. "No more games."

You challenged Nick to a sparring session. He slipped into his fighting stance.

(And my personal favorite!)
You had shaved Nick's head while he was sleeping as a prank and now he's out for blood.