nighttime vs evening

nighttime and evening both are nouns.

Word	Noun	Adjective	Verb	Adverb
nighttime	Yes	No	No	No
evening	Yes	No	No	No

nighttime (noun)	evening (noun)
the time after sunset and before sunrise while it is dark outside	the latter part of the day (the period of decreasing daylight from late afternoon until nightfall)
	a later concluding time period
	the early part of night (from dinner until bedtime) spent in a special way