Spray 13x9-inch baking pan with cooking spray.

Prepare popcorn according to package directions.  Remove all unpopped kernels.  Place into extra-large bowl sprayed with cooking spray; set aside.

Combine peanut butter, syrup and sugar in 8-cup glass measure.  Microwave on HIGH for 3 minutes, stirring after every minute or until mixture boils and sugar is 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 peanuts, before chocolate melts.  Pat mixture evenly into bottom of prepared pan.

Cool completely before cutting into 24 bars.