Preheat oven to 425°F.
Combine walnuts and brown sugar in small bowl. Place 3/4 cup of nut-sugar mixture on bottom of pie shell. Combine pumpkin, evaporated milk, sugar, eggs, pumpkin pie spice and salt in medium bowl; mix well. Pour batter over nuts.
Bake for 15 minutes. Reduce temperature to 350°F; bake for 40 to 50 minutes or until knife inserted near center comes out clean. Cool on wire rack.
Combine butter and remaining nut-sugar mixture; stir until moistened. Sprinkle over cooled pie. Broil about 5 inches from heat for 2 to 3 minutes or until bubbly. Cool before serving.