The game is won by 2 points, but what appears to be a Richie dunk that causes his hand to go through the backboard.

Immediately behind him is Bama players, and then BYU fans behind them. Meaning his team was on the other side of the court. This gives me 1 plausible conclusion.

Richie stole an inbound pass at midcourt after Bama's coach called a timeout with 8-ish seconds left in the game and ran it in for the game-winning dunk.