Heat oven to 350 degrees F. Coat a 9-inch loaf pan with cooking spray.
In a medium mixing bowl, sift together flour, baking powder, baking soda and salt.
In a large mixing bowl, using a mixer on medium speed, beat together banana, butter, granulated sugar, brown sugar and vanilla until creamy and well combined - about 2 minutes. Beat in eggs until well combined - about 2 minutes. Reduce mixer speed to low and beat in flour mixture until just combined. Divide 1/2 of of the batter into a medium bowl; stir in Nutella until combined.
Alternate spoonfuls of batter into loaf pan until all of the batter is used up. Swirl batter gently with a knife (not too much!). Bake 1 hour or until well risen, deep golden brown, and a toothpick inserted into bread comes out with moist crumbs attached.