Preheat oven to 350 degrees. Coat a 9 x 13 inch baking dish with cooking spray. Sprinkle pecans and coconut on bottom of dish. Prepare cake mix according to directions on box. Pour over pecans and coconut. Melt cream cheese and butter in saucepan over low heat till combined then add powdered sugar and mix well. Pour cream cheese mixture over cake batter. Bake in oven 40-45 minutes. Meanwhile heat evaporated milk and milky way bars in saucepan over low heat until milky way bars are melted and fully incorporated into the milk. Let cool slightly. When cake is done, poke holes in top of cake with fork or knife. Pour milky way mixture over top of cake. Let cool completely. Enjoy plain, or with whipped cream or ice cream.