HEAT oven to 350ºF.
PREPARE brownie batter as directed on package; pour into 9-inch pie plate sprayed with cooking spray. Bake 30 min. or until toothpick inserted in centre comes out clean. Immediately press down centre with another pie plate or measuring cup to make depression in centre of brownie, leaving thin brownie layer on bottom and 1-inch-wide rim around edge. Cool completely.
BEAT pudding mixes and milk with whisk 2 min. (Pudding will be thick.) Stir in 1 cup Cool Whip. Spoon into brownie shell; top with remaining Cool Whip and nuts.
REFRIGERATE 2 hours or until firm. Drizzle with caramel syrup just before serving.
serving size = 1 piece (115 g)