Preheat oven to 170°C. Grease muffin pan with oil.
In a bowl, whisk together banana, sugar, brown sugar, egg, vegetable oil and vanilla.
Add flour, baking soda, baking powder and salt and mix until there are no lumps.
Fill muffin tins 3/4 full. Top each muffin with about 1 teaspoon of Nutella and use a toothpick to swirl it into the batter.
Bake muffins for 15-17 minutes, or until a toothpick inserted in the center comes out clean.