Nick Young is preppin' for Game 3 of the NBA Finals in the most Swaggy P way possible ... by getting a brand new Cupid tattoo on his neck!!

The Warriors had some downtime in Cleveland on Tuesday, so Young hit up one of LeBron James' favorite tattoo artists -- Jimmy Hayden of Focused Tattoo -- for a quick ink sesh.

Swaggy went with an image of Cupid on the right side of his neck ... adding to his ever-growing collection of body art. 

Swaggy and Warriors take the court against the Cavs on Wednesday night -- less than 24 hours after Nick got his work done.

Think a fresh neck tattoo can have an effect on his game?