Yes, NOMINATIONS is a Scrabble word!

Letter values in Scrabble US: N 1, O 1, M 3, I 1, N 1, A 1, T 1, I 1, O 1, N 1, S 1.

Is it a valid word?

NOMINATIONS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the act of officially naming a candidate
the condition of having been proposed as a suitable candidate for appointment or election
an address (usually at a political convention) proposing the name of a candidate to run for election

Also: nominating speech, nominating address.