Add water to reserved pineapple juice to equal 1 cup. Combine cake mix, pudding mix, pineapple, and the cup of pineapple liquid, eggs, oil, and cinnamon. Beat at medium speed with electric mixer for 2 minutes. Stir in banana slices and nuts. Pour into two 9 inch layer cake pans which have been greased and floured. Bake at 350 degrees for 40-45 minutes. Frost with a cream cheese icing.