Preheat oven to 350°F (180°C). Spray an 8½x4½-inch loaf pan with baking spray with flour. Line pan with parchment paper, letting excess extend over sides of pan.
In a medium bowl, whisk together flour, pie spice, baking powder, salt, and baking soda.
In a large bowl, whisk together pumpkin, sugars, eggs, oil, and vanilla until smooth. Whisk in flour mixture until thick and smooth. Spread half of batter (about 1¼ cups or 375 grams) into prepared pan.
Spoon hazelnut chocolate spread into a pastry bag, and cut a ¼-inch opening in tip. Pipe half of spread evenly onto batter, leaving a ¼-inch border around edges. Using an off set spatula or skewer, gently swirl together spread and batter, avoiding sides of pan. Repeat procedure with remaining batter and remaining hazelnut chocolate spread.
Bake until a wooden pick inserted in center comes out with a few moist crumbs, 50 to 55 minutes. Let cool in pan for 10 minutes. Using excess parchment as handles, remove from pan, and let cool completely on a wire rack. Store in an airtight container for up to 3 days.