In a bowl, combine dry cake mix, nuts, brown sugar, and cinnamon. In an 8-inch glass baking dish, spoon cherry pie filling into bottom. Sprinkle cake mix mixture evenly over pie filling. Drizzle melted butter over top. Cook on Hi (max power) 12 to 14 minutes in the microwave or until topping is no longer doughy. Rotate dish during cooking if cake does not appear to be rising evenly. Let stand 5 minutes. Serve warm with whipped cream or vanilla ice cream.