BEAT cream cheese in large bowl with mixer until creamy. Gradually beat in milk. Add dry pudding mix, extract and nutmeg; beat 2 min. Gently stir in 1-1/2 cups COOL WHIP.
LINE 9x5-inch loaf pan with plastic wrap. Arrange 15 wafers, top-sides down, on bottom of pan; cover with 1/4 of the pudding mixture. Repeat layers 3 times. Top with 15 of the remaining wafers. Refrigerate 3 hours.
INVERT dessert onto plate; remove plastic wrap. Microwave chocolate and 1 cup of the remaining COOL WHIP in microwaveable bowl on HIGH 25 sec.; stir until chocolate is completely melted and mixture is well blended. Cool 1 min. Pour over dessert. Garnish with remaining COOL WHIP and wafers.