chewing vs chomping

chewing and chomping both are nouns.

Word	Noun	Adjective	Verb	Adverb
chewing	Yes	No	No	No
chomping	Yes	No	No	No

As nouns, chomping is a hyponym of chewing; that is, chomping is a word with a more specific, narrower meaning than chewing:

chewing: biting and grinding food in your mouth so it becomes soft enough to swallow
chomping: the act of chewing noisily

Other hyponyms of chewing include gumming, mumbling, rumination.

chewing (noun)	chomping (noun)
biting and grinding food in your mouth so it becomes soft enough to swallow	the act of chewing noisily