Line a 9x13 baking dish with parchment paper or grease with butter.
First melt the butter over low-medium heat on the stove in a large pot. Once the butter is melted, add in the mini marshmallows (BUT set aside 1 cup). Heat and stir for 5 minutes or so until melted. Remove from the heat and add in the rice cereal and crushed graham crackers.
Stir everything so that the marshmallow mix is covering everything. Then sprinkle in the chocolate chips and fold them in. Add in the reserved 1 cup of marshmallows and fold in as well.
Pour the mixture into your prepared 9x13 baking dish. Spray your hands with non-stick spray and press the mixture in the pan.
Optional- you can add some more chocolate chips on top.
Allow to set at room temperature for at least an hour. Then cut and serve! Or cover, seal, and leave on the counter.