Preheat the oven to 350°F (175°C).
In a large bowl, toss 8 peeled, seeded, and sliced extra green mangoes with 1 tablespoon of lime juice.
In a separate bowl, combine 1 cup of white sugar, 1/3 cup of all-purpose flour, 1/4 teaspoon of salt, and 1/2 teaspoon of ground nutmeg.
In a prepared double pie crust package, layer the sugar mixture and the sliced mangoes in several layers.
Dot the layers with 1/4 cup of butter.
Top the pie with the other half of the pie crust and prick it with a fork.
Bake the pie in the preheated oven for 1 hour, or until the mango has softened and the crust is golden brown.