1. Heat oven to 350°F. Cut each HERSHEY'S MINIATURES Chocolate Bar into about 8 pieces. Stir together marshmallows, chocolate bar pieces and nuts; set aside.
2. Prepare brownie mix according to package directions. Bake brownie 2 minutes less than recommended baking time; sprinkle marshmallow mixture over brownie surface. Continue baking 3 minutes or until marshmallows are puffed and lightly browned. Cool completely in pan on wire rack. Using wet knife, cut into squares. Makes about 24 brownies.