Preheat the oven to 400 degrees. Spray a rimmed baking sheet with nonstick spray. Place the squash, cut side down, on the baking sheet. Bake until tender, about 40 minutes. Turn cut side up and let cool.
Scoop the flesh out of the squash and transfer to a medium bowl. Mash well with a potato masher until smooth (you should have about 1 3/4 cups). Add the sugar, egg, pie spice and salt beating with a whisk until blended.
Sprinkle the gelatin over the evaporated milk in a large saucepan; whisk and then let stand until softened, about 5 minutes. Set the pan over medium heat, stirring frequently until the gelatin is completely dissolved, about 3 minutes. Stir in the squash mixture and cook, stirring constantly until the mixture just begins to boil, 5-6 minutes. Transfer to a large bowl. Refrigerate, stirring occasionally, until the squash mixture mounds and begins to set, about 1 hour.
Gently whisk the squash mixture until smooth. With a rubber spatula, fold in the whipped topping. Pour the mixture into the crust. Sprinkle with the pecans. Refrigerate until set and firm, at least 2 hours or up to overnight.
GOOD IDEA: For an additional 1 points value, drizzle each serving of pie with 1 tablespoon chocolate-fudge syrup.