Spoon half the COOL WHIP into bowl; refrigerate to thaw. Return remaining COOL WHIP to freezer. Prepare cake batter and bake as directed on package for 2 (9-inch) round layers, adding dry pudding mix to cake mix before mixing with liquid ingredients. Cool cakes in pans 10 min.; invert onto wire racks. Remove pans. Cool cakes completely.
Meanwhile, microwave caramels and water in microwaveable bowl on HIGH 1-1/2 min. or until caramels are completely melted and mixture is well blended, stirring every 45 sec. Cool slightly.
Beat cream cheese in large bowl with mixer until creamy. Add caramel sauce; mix well. Blend in thawed COOL WHIP. Stack cake layers on plate, filling and frosting top with cream cheese mixture. Refrigerate while preparing chocolate glaze and garnishes.
Melt 2 oz. chocolate as directed on package. Dip half of each wafer in chocolate; place on waxed paper-covered baking sheet. Top with nuts. Refrigerate until ready to use.
Microwave frozen COOL WHIP and remaining chocolate in microwaveable bowl 3 min. or until chocolate is completely melted and mixture is well blended, stirring after each minute. Cool 10 min.
Spread COOL WHIP mixture onto top of cake. Garnish with wafers. Keep refrigerated.