Microwave the marshmallows and butter in a microwave-safe bowl for 2 minutes. Stir and microwave another minute. Stir in peanut butter until smooth. Mix in both crispy rice cereals.
Using wet hands, press the crispy cereal mixture evenly into the baking dish. Top with chopped Reese's cups.
Microwave the chocolate chips until melted, adding 1 Tablespoon of milk, if need, to thin the mixture. Drizzle onto the top of the crispy treats. Repeat with the peanut butter chips. Let cool, cut and serve!
** Nutritional information is an estimate and may vary.