In a microwave safe bowl, heat the chocolate chips, peanut butter, butter, and vanilla for 30 second increments, stirring well between, until melted.

Pour this over the chex cereal and stir the cereal to coat.

Add the powdered sugar to two gallon storage bags.

Divide the chocolate coated cereal between the bags and shake to coat with the powdered sugar.

Allow this to set for 1 hour.

Before serving, add in the mini reeses cups and reeses pieces, and mix.