Pour cereal into a large bowl and set aside
Combine chocolate chips, peanut butter, and butter in 1 qt bowl
Microwave on High 1 to 1.5 minutes until smooth, stirring after 1 minute
Stir in vanilla
Pour chocolate mixture over cereal, stirring until all pieces are evenly coated
Pour cereal into resealable plastic bag with powdered sugar and shake until evenly coated
Spread on waxed paper to cool