Preheat oven to 350F degrees. Line a 13 X 9 X 2" baking pan with foil; spray with nonstick cooking spray and set aside. Follow package directions to prepare brownie mix. Spread batter evenly in foil-lined pan. Sprinkle cereal evenly over batter; press lightly. Sprinkle toffee bits evenly over cereal. Bake until brownies are set, 30-35 minutes. Cool in pan on wire rack. Lift foil to remove brownies from pan to cutting board. Fold foil back to cut brownies.