Yes, PENNINES is a Scrabble word!

Letter values in Scrabble US: P 3, E 1, N 1, N 1, I 1, N 1, E 1, S 1.

Is it a valid word?

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

a system of hills in Britain that extend from the Scottish border in the north to the Trent River in the south; forms the watershed for English rivers

Also: pennine chain.