In a mixing bowl, combine the dry cake mix, oats and butter until blended; set aside ¾ c. for topping. Add egg to the remaining crumb mixture and mix well. Press into a Pam sprayed 12-inch pizza pan. Build up edges and flute if desired. Bake at
350 degrees for 12 minutes. Spread pie filling over crust to within 1 in. of edges. Combine the nuts (optional), brown sugar, cinnamon and reserved crumb mixture; sprinkle over filling. Bake for 15-20 minutes or until lightly browned. Cool on wire rack. Refrigerate any leftovers.