Preheat oven to 425°F.
Arrange peaches in pie shell. Combine sweetened condensed milk, eggs, butter, lemon juice, cinnamon and nutmeg in large mixer bowl; beat until smooth. Pour over peaches.
Bake for 10 minutes. Sprinkle with Streusel Topping. Reduce temperature to 350°F; bake for additional 55 to 60 minutes or until knife inserted near center comes out clean. Cool on wire rack.
For Streusel topping: Combine brown sugar, flour and walnuts in medium bowl. Cut in butter with pastry blender or two knives until mixture resembles coarse crumbs.
1/3 cup all-purpose flour
1/3 cup packed brown sugar
1/3 cup chopped walnuts
2 tablespoons butter or margarine, chilled