Preheat the oven to 350°F (175°C).
Grease a 9x13-inch baking dish.
Pour the canned peaches into the dish, including the syrup.
Spread the peaches evenly across the bottom.
Sprinkle the dry cake mix evenly over the peaches.
Drizzle the melted butter over the cake mix, covering it completely.
Sprinkle cinnamon and nuts on top, if desired.
Bake in the preheated oven for 45-50 minutes until golden brown.
Remove from oven and let it cool slightly before serving.
Serve warm with whipped cream or ice cream, if desired.