Cook and stir chocolate chips, peanut butter, and butter together in a pot over low heat until melted, about 5 minutes. Place cereal squares in a bowl and pour chocolate mixture over cereal and stir until evenly coated. Add confectioners' sugar to coated cereal and stir to coat. Allow puppy chow to cool.
Mix puppy chow, peanuts, marshmallows, sunflower seeds, chocolate pieces, and raisins together in a large bowl.