In a large bowl, whisk together the flour, baking soda, cinnamon, salt, and oats.
Separately, beat the melted butter, maple syrup, brown sugar, granulated sugar, egg yolk, pumpkin purée, and vanilla extract until smooth.
Combine wet ingredients with dry, stirring until just mixed. Fold in chocolate chips. Scoop 1 1/2 tablespoons of dough per cookie onto a parchment-lined baking sheet, spacing them 3 inches apart. Slightly flatten each cookie.
Bake at 350°F for 12-14 minutes until edges are lightly browned.
Cool on the baking sheet for 5 minutes before transferring to a wire rack to finish cooling.