Here are some examples:
* "I'm going to nosh on some popcorn while I watch the movie."
* "Let's nosh on some pizza after the game."
* "He's always noshing on something."
It's also sometimes used as a noun to refer to the food itself:
* "I had a nosh of cheese and crackers before dinner."
* "The kids were all hungry for a nosh."
"Nosh" is a Yiddish word, and it's a very informal term.