Preheat your oven to 350°F (175°C).
Grease a 9x13 inch baking dish.
Spread the sliced peaches evenly in the bottom of the dish.
Sprinkle granulated sugar over the peaches.
Evenly sprinkle the dry cake mix over the sugar and peaches.
Drizzle melted butter evenly over the cake mix.
Sprinkle ground cinnamon and nuts, if using, on top.
Bake in the preheated oven for 40-45 minutes, or until golden brown.
Remove from the oven and let it cool slightly.
Serve warm, optionally with vanilla ice cream.