Toss the sliced green mango with the lime juice in a large bowl. In a separate bowl, toss together the sugar, flour, salt, and nutmeg. Layer the sugar mixture and the sliced mangoes in several layers in the pie shell bottom. Dot with butter, then top with the other half of the pie crust. Prick with a fork.
Bake in preheated oven for 1 hour, until the mango has softened and the crust is golden brown.