Prepare the Oven: Preheat the oven to 350°F (175°C).

Lightly grease a 9×13-inch baking dish.

Prepare the Peach Filling: Pour the two undrained cans of peaches and one drained can into the baking dish.

Add the vanilla extract, cinnamon, and nutmeg if using.

Gently stir until evenly combined: Spread the peaches into an even layer.

Add the Cake Mix: Sprinkle the dry cake mix evenly over the peaches.

Do not stir: Use a spatula to spread the mix into an even layer if needed.

Add the Butter: Slowly drizzle the melted butter over the entire surface of the cake mix.

Cover as much of the dry mix as possible to encourage even browning.

Sprinkle the chopped pecans evenly over the top if using.

Bake for 45 to 50 minutes, until the topping is deep golden brown and the peach filling is bubbling around the edges.

If small dry patches remain after 30 minutes, drizzle 1 to 2 tablespoons of additional melted butter over those areas.

Cool: Allow the cake to cool for 10 minutes before serving so the filling can thicken slightly.

Serve warm with vanilla ice cream, whipped cream, or fresh peach slices if desired.