Preheat oven to 350°F. Line an 8-inch square pan with parchment, leaving a sling.
Warm the chocolate-hazelnut spread in the microwave 10–15 seconds until pourable; set aside.
Whisk flour, cinnamon, pumpkin pie spice, baking powder, baking soda, and salt in a bowl.
Stir melted butter, oil, brown sugar, and granulated sugar in a large bowl until glossy.
Whisk in vanilla and pumpkin puree until smooth.
Fold dry ingredients into wet just until combined; do not overmix.
Spread batter into the prepared pan and smooth the top.
Dollop warmed chocolate-hazelnut spread over batter. Swirl with a knife for ripples.
Sprinkle hazelnuts and chocolate chips on top if using.
Bake 28–32 minutes, until the center is set and a toothpick shows a few moist crumbs.
Cool in pan 20 minutes. Lift out, cool completely, then slice into bars.