game of chance vs craps

game of chance and craps both are nouns.

Word	Noun	Adjective	Verb	Adverb
game of chance	Yes	No	No	No
craps	Yes	No	No	No

As nouns, craps is a hyponym of game of chance; that is, craps is a word with a more specific, narrower meaning than game of chance:

game of chance: a game that involves gambling
craps: a gambling game played with two dice; a first throw of 7 or 11 wins and a first throw of 2, 3, or 12 loses and a first throw of any other number must be repeated to win before a 7 is thrown, which loses the bet and the dice

Other hyponyms of game of chance include fan tan, fantan, drawing, lottery, roulette, banking game.

game of chance (noun)	craps (noun)
a game that involves gambling	a gambling game played with two dice; a first throw of 7 or 11 wins and a first throw of 2, 3, or 12 loses and a first throw of any other number must be repeated to win before a 7 is thrown, which loses the bet and the dice
	expressions used when two dice are thrown and both come up showing one spot