Yes, MANILA is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, N 1, I 1, L 1, A 1.

Is it a valid word?

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

a strong paper or thin cardboard with a smooth light brown finish made from e.g. Manila hemp
the capital and largest city of the Philippines; located on southern Luzon

Also: manila paper, manilla paper, capital of the philippines.