Pour powdered sugar in a large ziploc bag; set aside.

Pour cereal and ¾ cup marshmallows into a very large mixing bowl.

In a small saucepan, melt chocolate chips and peanut butter together over low heat, stirring constantly. Remove from heat and stir in ¾ cup marshmallows. Stir until the marshmallows melt and the mixture is smooth.

Pour the mixture over the cereal and marshmallows and gently stir until everything is coated. Transfer the mixture to the ziploc bag of powdered sugar, seal, and shake until all the cereal is coated with powdered sugar.

Cool before serving.