niceness vs courtesy

niceness and courtesy both are nouns.

Word	Noun	Adjective	Verb	Adverb
niceness	Yes	No	No	No
courtesy	Yes	No	No	No

As nouns, courtesy is a hypernym of niceness; that is, courtesy is a word with a broader meaning than niceness:

Other hypernyms of niceness include good manners.

niceness (noun)	courtesy (noun)
the quality of nice	a courteous or respectful or considerate act
the quality of being difficult to detect or analyze	a courteous manner
a courteous manner that respects accepted social usage	a courteous or respectful or considerate remark