Bake cake according to directions in a 9x13 pan. In a saucepan over medium heat, combine pineapple with juice, sugar, pudding, and coconut. Simmer 5 minutes. Using a wooden spoon handle, poke holes in warm cake. Slowly pour pineapple mixture over cak and spread evenly. Cool. Spread whipped topping venly over cake and sprinkle with nuts.
Chill at least 2 hours before serving.