happy chance vs good luck

happy chance and good luck both are nouns.

Word	Noun	Adjective	Verb	Adverb
happy chance	Yes	No	No	No
good luck	Yes	No	No	No

As nouns, happy chance and good luck are synonyms defined as:

Other synonyms of happy chance include break.

happy chance (noun)	good luck (noun)
an unexpected piece of good luck	an unexpected piece of good luck
	a stroke of luck
	an auspicious state resulting from favorable outcomes