Is NITES a Wordle Word?

Yes. NITES is a valid Wordle word.

It is not on the Wordle answer list, so it is unlikely to be a daily answer.

Plurals ending in S are almost never chosen as Wordle answers.

What does NITES mean?

The period between sunset and sunrise, when a location faces far away from the sun, thus when the sky is dark.“How do you sleep at night when you attack your kids like that!?”
(Astronomy) The period of darkness beginning at the end of evening astronomical twilight when the sun is 18 degrees below the horizon, and ending at the beginning of morning astronomical twilight.
(Legal) Often defined in the legal system as beginning 30 minutes after sunset, and ending 30 minutes before sunrise.

6 more noun definitions

An evening or night spent at a particular activity.“a night on the town”
A night (and part of the days before and after it) spent in a place away from home, e.g. a hotel.“I stayed my friend's house for three nights.”
Nightfall.“from noon till night”
Darkness (due to it being nighttime).“The cat disappeared into the night.”
A dark blue colour, midnight blue.
A night's worth of competitions, generally one game.

Definition from Wiktionary, available under the CC BY-SA license.

Starter word rating: GoodIn the top 6% of all valid Wordle words for testing common letters.
Vowels: I, E
Unique letters: 5 of 5
Common letters: I, T, E

Hard-mode trap: 12 valid words fit the pattern _ITES. If you reach it, you may need several guesses to find the last letter.

Letter ratings use how often each letter appears in Wordle answers.

Tap its tiles to the colours Wordle showed, and the Wordle Solver lists every word that still fits, with the best next guess.