Preheat oven 350°F.Line the muffin tin with muffin cups or spray with nonstick cooking spray. Set aside. In a medium bowl, add flour, cocoa powder, sugar, baking soda, cinnamon, and salt. Mix until completely combined.
In a large bowl mash the banana. Add oil, maple syrup, and vanilla. Mix well.
Pour dry ingredients into wet ingredients. Mix until incorporated.Stir in zucchini then fold in ½ cup of chocolate chips. Spoon batter into the prepared muffin tin using a 3 tbsp cookie scoop. Sprinkle muffins with the remaining ¼ cup chocolate chips.
Bake 20-23 minutes or until a toothpick comes out clean when poked in the middle. Let cool slightly before transferring or enjoying. Store in an airtight container for 4-5 days.