Jadon Sancho, Fred, Anthony Martial and Facundo Pellistri all scored for the Red Devils as they coasted to victory in Thailand.
Liverpool were already three goals down when Nunez came off the bench.
The Uruguay striker almost pulled one back in the 87th minute, but blazed his effort over the bar from 10 yards.
When asked about Nunez after the match, Klopp said: “He is a number nine and he can play on the wing as well. We will see where he will play.
“But what you could see is the boys were already searching for him.
“It was his third session (since arriving for pre-season training) and I think after the third sprint his lungs were nearly ready to explode.
“We nearly killed him with these balls but he offered the runs and the boys wanted to pass the ball, that is for sure one of his strengths. He was dangerous, all these kinds of things.
“So Darwin, we will see. I think his profile is a proper number nine so that’s helpful with speed and aggression and using his body, all these kinds of things.”