Yes, NECTARINE is a Scrabble word!

Letter values in Scrabble US: N 1, E 1, C 3, T 1, A 1, R 1, I 1, N 1, E 1.

Is it a valid word?

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

variety or mutation of the peach bearing fruit with smooth skin and (usually) yellow flesh
a variety or mutation of the peach that has a smooth skin

Also: nectarine tree, prunus persica nectarina.