In a large bowl, combine the Rice Krispie cereal, miniature chocolate chips, graham cracker crumbs, and one cup of the miniature marshmallows. Stir to combine and set aside.
In a large pot, melt the butter. Add the remaining mini marshmallows and stir until they are completely melted and incorporated. Pour the marshmallow mixture over the dry ingredients. With a spatula, mix together until everything is well combined and coated.
Pour the mixture into a greased 13-by-9-inch baking pan or onto a sheet of wax paper. With a greased spatula, evenly spread the mixture into an even layer and the shape of the pan.