Here is a similar version of the carrot cake I made a while back. Look here for the recipe.
*Heat oven to 350°F. Prepare cake batter as directed on package; stir in carrots, pineapple
*Pour into 2 (9-inch) square pans. Bake 25 to 30 min. or until toothpick inserted in centers comes out clean. Cool in pans 10 min.; invert onto wire racks. Remove pans. Turn cakes over; cool completely.
Now for the icing you will need:
2 pkg. (8 oz. each) Cream Cheese, softened
2 cups powdered sugar
1 tub (8 oz.) COOL WHIP Whipped Topping, thawed
*Beat cream cheese and sugar until well blended. Whisk in COOL WHIP.
*Stack cake layers on plate, spreading frosting between layers and on top and sides of cake. Top with remaining nuts. Keep refrigerated.