1. Heat oven to 425 degrees F.
2. In bowl, combine piecrust mix and pecans. Stir in just enough water until dough begins to form a ball. Place in 9-inch pie plate; press evenly over bottom and up side (not on rim).
3. In large bowl, mash sweet potatoes. With a whisk, stir in sweetened condensed milk, eggs, pumpkin pie spice, vanilla and salt until smooth. Pour into piecrust.
4. Bake in 425 degrees F oven for 15 minutes. Reduce temperature to 350 degrees F. Bake until center is set or knife comes out clean, about 30 minutes. Let pie cool on wire rack. Serve warm or at room temperature with whipped topping and additional chopped pecans. Makes 10 servings.