Yes, MACHINE is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, C 3, H 4, I 1, N 1, E 1.

Is it a valid word?

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

any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks
an efficient person
an intricate organization that accomplishes its goals efficiently
a device for overcoming resistance at one point by applying force at some other point
a group that controls the activities of a political party
a motor vehicle with four wheels; usually propelled by an internal combustion engine

Also: simple machine, political machine.