Beat pudding mix and milk in large bowl with whisk 2 min. Gently stir in 2-1/2 cups COOL WHIP.
Layer half each of the cake cubes, pudding mixture and strawberries in 2-1/2-qt. serving bowl; top with 2-1/4 cups marshmallows. Repeat layers of cake, pudding mixture and strawberries. Top with remaining COOL WHIP; sprinkle with nuts and remaining marshmallows. Cover.