Measure the cereal into a large bowl and set aside.
Line a baking sheet with wax paper and set aside.
In a microwave-safe medium bowl, microwave the chocolate chips, peanut butter, and butter for 1 minute, then stir. Continue microwaving in 30-second intervals, stirring in between.
Pour in the cereal and gently mix until thoroughly coated.
Transfer the mixture to a 2-gallon Ziploc bag and add the confectioner’s sugar. Seal the bag and shake until all the cereal is coated.
Spread the cereal out onto the baking sheet and sprinkle on the M&M candies.
Let sit for 15 minutes at room temperature to cool and serve.
Store leftovers in an airtight container.