Yes, NIRVANAS is a Scrabble word!

Letter values in Scrabble US: N 1, I 1, R 1, V 4, A 1, N 1, A 1, S 1.

Is it a valid word?

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

(Hinduism and Buddhism) the beatitude that transcends the cycle of reincarnation; characterized by the extinction of desire and suffering and individual consciousness
any place of complete bliss and delight and peace

Also: promised land, shangri-la.

Not playable in Scrabble US: EDEN.