Preheat the oven to 350°(F). Set the pie shells aside while you prepare the pumpkin batter.
In a large bowl, beat together the pumpkin, evaporated milk, eggs, 1 cup of sugar, and 4 teaspoons of pumpkin pie spice until smooth and creamy.
Pour half the batter into one of the unbaked pie shells, and the other half of the batter into the other pie shell.
Divide the cake mix in half. Sprinkle each half of the dry cake mix over one of each of the pies, making sure the pumpkin batter is completely covered.
Drizzle the melted butter over each of the pies, also dividing the butter equally. Top the pies with chopped nuts.
In a small bowl, mix together the 2 tablespoons of sugar with 1 teaspoon of pumpkin pie spice. Divide the mixture in half and sprinkle over the top of the nuts of each pie.
Bake the pies at 350°(F) for 45–55 minutes, or until a knife inserted in the center comes out clean, or the center is no longer jiggly.
Allow the pies to cool on a wire rack. Store the leftover pie, covered, in the refrigerator.