Preheat oven to 350°. Line 13 X 9-inch baking pan with heavy-duty aluminum foil. Spray foil with nonstick cooking spray; set aside.
Stir brownie mix, 1-1/2 cups chocolate chips, Hellmann's® or Best Foods® Real Mayonnaise, eggs and water in medium bowl just until combined. Pour into prepared pan.
Bake 25 minutes or until center is set. Cool completely on wire rack.
Microwave 2 tablespoons milk in small microwave-safe bowl at HIGH 30 seconds or until hot. Add remaining 1/2 cup chocolate chips and let stand 2 minutes; stir until smooth. Combine confectioners sugar with 1 to 1-1/2 tablespoons milk in another small bowl until mixture is thin enough to spread but not runny.
Trim brownie to 12 X 8-inch rectangle. Cut in 1/2 crosswise. Evenly spread chocolate glaze on 1/2 of the brownie and confectioners sugar glaze on other 1/2. Refrigerate 30 minutes or until glaze is firm. Cut each 1/2 into 36 (1-inch) squares. Arrange alternately on rectangular platter.