Green’s Dictionary of Slang

1. a bite, a mouthful.

1966		T. Keyes All Night Stand 89: Fat kraut who can think of nothing better than to give a great chomp at her breast.
2001		S. King Dreamcatcher 128: Something small, but with big teeth, would soon spring at him, taking a great big chomp out of his balls.

2. food.

1992

R.G. Barrett White Shoes 109: The ‘chomp’ was equal to the surroundings.