Put the butter and 4 cups of mini marshmallows into a large microwave safe bowl. The butter should be on top of the marshmallows. Microwave in 30 second increments until the butter is melted and the marshmallows are puffed up. Stir until the marshmallows are deflated, smooth and the butter is well incorporated. Pour in the Rice Krispies and the graham cracker crumbs. Stir until everything is combined. Let cool briefly and then mix in the remaining marshmallows and chocolate chips. Press into a sprayed 13X9 pan. Let them cool and then cut into squares. Enjoy!