Step 1: Preheat the oven to 350°F (175°C). Line a muffin tin with paper liners or spray with non-stick spray.
Step 2: In a large mixing bowl, combine the mashed bananas, shredded zucchini, peanut butter, canola oil, egg, and vanilla extract. Whisk until smooth.
Step 3: In a separate bowl, whisk together the flour, baking soda, and salt.
Step 4: Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.
Step 5: Fold in the brown sugar and chocolate chips.
Step 6: Spoon about a tablespoon of batter into each muffin cup, add a heaping tablespoon of Nutella, then top with more batter.
Step 7: Bake for 18-20 minutes or until a toothpick comes out clean.
Step 8: Allow muffins to cool in the tin for 5 minutes before transferring to a wire rack.
