HEAT oven to 350°F. Coat an 8 x 8-inch baking pan lightly with no-stick cooking spray. COMBINE brownie mix, oil, water and egg in medium bowl. Stir 50 strokes with spoon. Spread evenly in prepared pan. BAKE 30 to 32 minutes. Cool completely. Cut into cubes. Place half of cubes in 1 1/2-quart serving dish. STIR caramel topping in bowl until smooth. Whisk in whipped topping until blended. Spread half on top of brownie cubes in dish. Make another layer of remaining brownie cubes and topping. Sprinkle with mini chocolate chips. Drizzle with additional caramel topping, if desired.