Preheat oven to 375 degrees.
Line baking sheet with parchment paper.
Whisk together flour, baking soda, pumpkin spice, and salt in a bowl.
Using a mixer beat the butter until smooth. Add both sugars and vanilla beating on medium speed until the mixture is light and fluffy. Continue to beat while adding the pumpkin puree.
Once all of these ingredients are well blended slowly begin to add in the flour mixture. Turn off the mixer and using a rubber spatula fold in the flour mixture until it begins to disappear.
Gently add in the butterscotch chips and chopped walnuts.
Using an ice cream scoop measure out the cookie dough balls.
Place each dough ball on the baking sheet leaving space between each cookie. Roll the dough into a ball for baking.
Bake at 375 degrees for 15-16 minutes.
The edges of the cookies should be a golden color.
Allow the cookies to cool slightly on the baking sheet before moving to a cooling rack.