nowadays vs nonce

nowadays and nonce both are nouns.

Word	Noun	Adjective	Verb	Adverb
nowadays	Yes	No	No	Yes
nonce	Yes	No	No	No

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

nowadays: the period of time that is happening now; any continuous stretch of time including the moment of speech
nonce: the present occasion

Other hyponyms of nowadays include now, here and now, moment, present moment, date, time being, today, tonight.

nowadays (noun)	nonce (noun)
the period of time that is happening now; any continuous stretch of time including the moment of speech	the present occasion

nowadays (adverb)	nonce (adverb)
in these times