Lay out a large piece of parchment paper on the table.
In a large microwavable bowl, melt the chocolate chips, butter, and peanut butter. Do 30 seconds, then stir. Repeat until smooth and creamy.
Pour the six cups of chex into the bowl and fold until all is covered.
Put 1 cup of powdered sugar into a gallon ziploc bag then add the chocolatey chex mix. Top with ½ cup more powdered sugar. Zip the top closed then shake, shake, shake!
Pour onto the parchment paper and let harden for 1-2 hours.
Mix in m&m's if preferred.
Enjoy or put in a storage container for up to 1 week.