Line a 9x13 pan with parchment paper, or grease with non-stick cooking spray.

Place 8 cups of Chocolate Chex in a large bowl, set aside.

In a medium-sized pot, melt the butter and peanut butter together over medium heat. Add the marshmallows and stir frequently until melted and completely blended with the butter and peanut butter.

Remove pot from heat and pour melted contents over the chocolate chex. Mix together with a spatula until well coated. Fold in the peanut butter chips.

Pour contents of the bowl into the center of a 9x13 pan. With a spatula, or with your hand enclosed in a greased baggie, spread out the chex evenly into all four corners of the pan.

Let pan sit at room temperature for a half hour. Cover and chill in the fridge for another hour.

Slice into desired square sizes and serve.