Preheat oven to 375.
Place pie crust in 9-inch glass pie pan as directed on box for one-crust filled pie.
In large bowl combine pie filling ingredients in order given (from pumpkin to evaporated milk)
Streusel topping: Combine brown sugar and flour; cut in the butter until crumbly. Stir in chopped pecans. Set aside.
Pour filling into crust lined pie pan. Bake 50 to 60 minutes or until knife inserted two inches from center comes out clean.
Remove pie from oven and sprinkle streusel over pie filling .
Return pie to the oven, cover crust with foil, and bake for an additional 15 minutes.
Cool completely, about 1 hour.