Preheat oven to 350 degrees. In a bowl, blend sugar, flour, cinnamon, and nutmeg. Add sliced apples, lemon juice and water. Stir and place in 8x11 greased baking dish. In a separate bowl, blend butter and cake mix until crumbly. Add nuts. Sprinkle dry mixture over apples. Bake for 35-40 minutes at 350 degrees.