Pour the candy melts into a glass microwavable safe dish. Heat in 30 second increments, stirring occasionally until melted. Let cool a few minutes.
Pour the melted dark chocolate over the Chex cereal and gently stir until all the cereal is coated with melted chocolate.
Divide the 2 cups of powdered sugar between the 2 large freezer bags.
Divide the chocolate coated cereal between the 2 bags of powdered sugar, seal shut and gently shake each bag to coat the cereal with the powdered sugar.
Add the Chocolate Lucky Charms Cereal to the puppy chow.
Store the puppy chow in an airtight container in the fridge