Preheat oven to 350 degrees, and grease cookie sheets with non-stick spray.
In a medium bowl, combine flour, oats, baking soda and powder, cinnamon, nutmeg, and salt. Set aside.
Using a mixer and large bowl, combine the butter and sugar until well blended. Beat in pumpkin, egg, and vanilla until well combined. Slowly add in the dry ingredients until it comes together. Stir in the chocolate chunks.
Drop round spoonfuls onto greased cookie sheets. Bake 15-17 minutes on the center rack. Cool slightly while on the baking sheet, and then remove cookies onto a wire cooling rack. Store in an air tight container or plastic zip bag.
These would also be delicious frosted!