Preheat the oven to 350°F (175°C).

In a large mixing bowl, combine mashed sweet potatoes, sugar, and melted butter. Mix until smooth.

Add eggs, vanilla extract, cinnamon, and nutmeg. Mix until well blended.

Stir in evaporated milk until the mixture is smooth.

Pour the sweet potato mixture into the unbaked pie crust.

Smooth out the top with a spatula.

Bake for 45 to 50 minutes, until the edges are set and the center has only a slight jiggle.

Let the pie cool on a wire rack before serving.