Prepare popcorn according to package directions. Remove all unpopped kernels. Place popped corn in extra-large bowl sprayed with cooking spray; set aside.
Combine peanut butter, corn syrup and sugar in 8-cup glass measure. Microwave on HIGH 3 minutes, stirring after every minute or until mixture boils and sugar is completely dissolved. Let mixture cool 3 minutes.
Pour peanut butter mixture over popped corn; toss gently with two wooden spoons, sprayed with cooking spray, until popcorn is coated evenly. Quickly stir in chocolate covered peanuts to avoid excessive melting of chocolate. Pat mixture evenly into pan.