Add cereal and ¾ cup of peanut butter chips to a large mixing bowl and set aside.
Add parchment paper to 13x9 baking dish and set aside.
In a saucepan over medium heat, melt the butter and peanut butter. Once melted and smooth, add 15 ounces of the marshmallows. Continue to stir and move until fully incorporated. Pour mixture over cereal and quickly stir together.
Fold in all but a handful of the remaining marshmallows.
Transfer cereal to baking dish and use a spatula to press into a even layer in the baking dish.
Sprinkle top of flattened mixture with remaining peanut butter chips and marshmallows. Press into the mixture some.
Place in refrigerator to cool for at least 2 hours. Remove and cut into 16 bars.