Preheat oven to 375 degrees F (190 degrees C). Prepare a 9x13-inch pan with cooking spray.
Mold the pie crust to fit the pan. It may be thin in some spots; that's ok, just try to get it as even as possible.
Beat butter and brown sugar together with an electric mixer in a large bowl until smooth. Beat 1 egg into the butter until completely blended; repeat with the second egg.
Mix flour, pumpkin pie spice, baking soda, and salt together in a separate bowl. Add to pumpkin mixture and beat to combine. Fold butterscotch chips and pecans into the mixture; pour into the pie crust.
Bake in preheated oven until a knife inserted in the center comes out clean, 25 to 35 minutes. Dust with confectioners' sugar.