Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius) and line two large baking sheets with parchment paper.
In a large mixing bowl, cream together the softened butter and brown sugar until light and fluffy.
Beat in the egg, pumpkin puree, and vanilla extract until smooth.
In a separate medium bowl, whisk together the flour, baking soda, cinnamon, pumpkin pie spice, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the rolled oats and the chocolate chips by hand.
Scoop rounded tablespoons of dough onto the prepared baking sheets, spacing them 2 inches apart.
Bake for 10 to 12 minutes or until the edges are lightly golden and the centers are set.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.