Loaded Peanut Butter Chex™ Party Mix

In 1-gallon resealable food-storage plastic bag, mix together powdered sugar and baking cocoa; set aside. In medium bowl, measure 3 cups cereal; set aside. In small microwavable bowl, microwave chocolate chips, peanut butter and butter uncovered on High 30 seconds; stir. Microwave 15 to 30 seconds longer or until mixture can be stirred smooth. Pour mixture over cereal in bowl; stir until evenly coated. Pour coated cereal into plastic bag with powdered sugar mixture. Seal bag; shake until well coated. Spread on cooking parchment paper to cool, about 20 minutes. In large bowl, toss together cooled coated cereal, remaining 3 cups cereal, the peanuts and peanut butter cups. Store in airtight container.