Muddy Buddies

1.Add Chex into a large bowl and set aside.
2.In a large microwaveable bowl, microwave chocolate chips, peanut butter and butter uncovered on High 30 seconds; stir. Microwave about 30 seconds longer or until mixture can be stirred smooth. Stir in vanilla.
3.Pour mixture over cereal, stirring until evenly coated. Pour into 2-gallon resealable food-storage plastic bag.
4.Add powdered sugar. Seal bag; shake until well coated. Spread on parchment paper to cool. Store in airtight container in refrigerator.