Stir together first 5 ingredients. Pour into a lightly greased 13- x 9-inch baking dish. Sprinkle cake mix evenly over pumpkin mixture; sprinkle evenly with pecans. Drizzle butter evenly over pecans.
Bake at 350° for 1 hour to 1 hour and 5 minutes or until golden brown. Remove from oven, and let stand 10 minutes before serving. Serve warm or at room temperature with Whipped Cream, if desired. Sprinkle with nutmeg, if desired.
Note: For testing purposes only, we used Betty Crocker Super Moist Butter Recipe Yellow Cake Mix.