Easy Win
Fight in the disco ring and throw your opponent out of the ring. When they stand up, press L2 to make them do the YMCA dance. Continue to do this until the timer runs out.
Submitted by Hovey. 

Unlock All Wrestlers
Press R1, R1, R1, R1, L1, L1, L1, L1, R2, R2, R2, R2, L2, L2, L2, L2, Select at the title screen (you will hear a sound to confirm it worked) to unlock all the wrestlers in the game.
Submitted by Robert_Bennett. 

Go to: WCW Nitro Info Page | nGaming Home Page.