Yes, MONOLOGUES is a Scrabble word!

Letter values in Scrabble US: M 3, O 1, N 1, O 1, L 1, O 1, G 2, U 1, E 1, S 1.

Is it a valid word?

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

speech you make to yourself
a long utterance by one person (especially one that prevents others from participating in the conversation)
a (usually long) dramatic speech by a single actor