Place popcorn in large bowl; set aside.
In microwave safe bowl, combine butter, peanut butter and chocolate chips.
Microwave 2 minutes; stir until smooth.
Pour chocolate mixture over popcorn and stir until well coated.
Sprinkle confectioners’ sugar over popcorn and stir until coated.
Cool to room temperature before serving.
Store in airtight container, refrigerated, up to 24 hours.