1. Bake cake according to directions listed on the box.
2. Once cake has cooled to room temperature cut cake in half from side to side through the middle.
3. Beat milk and pudding mix together in bowl.
4. Add thawed whip topping and mix together well.
5. Spread pudding mixture over top of bottom half of cake.
6. Replace top of cake and spread rest of the pudding mixture over top of cake and down the sides.
7. Refrigerate until pudding is set no longer than 24 hours.
8. Sprinkle with nuts and serve.