Pre heat oven to 350 degrees and line two large baking sheets with parchment paper.
In a large bowl, whisk the flour, pumpkin pie spice, baking soda , cinnamon, and salt together until well combined. Stir in the oats.
In the bowl of a stand mixer (or using a hand mixer) cream the butter and sugar together. Add the egg, pumpkin, and vanilla extract and blend until well combined and creamy.
Slowly add the dry ingredients to the bowl and mix on low speed, until combined. Add the chocolate chips and mix again.
Scoop the dough onto two parchment lined baking sheets, spacing 2-3 inches apart. Place the baking sheets in the refrigerator to chill for 1 hour. You can also chill the dough in the bowl and scoop onto baking sheets after it's chilled.
Bake for 13-15 minutes, or until browned at the edges but soft in the middle. Let the cookies rest on the baking sheets for a few minutes before transferring them to a wire rack to cool. Sprinkle with flaky sea salt, if using.
Enjoy pumpkin season!