Preheat oven to 350 degrees. Prepare a 12 cup muffin tin with liners or nonstick spray.
In a large bowl mix together sugar, brown sugar, and canola oil. Mix until well combined, about 45 seconds. Add Greek yogurt, milk, vanilla, and egg. Mix until just combined.
In a separate bowl whisk together flour, baking powder, baking soda, cocoa powder and salt. Gradually add flour mixture to yogurt mixture. Mix until just combined.
Fold in zucchini and chocolate chips.
Fill muffin cups about 3/4 of the way full. Sprinkle a few extra chocolate chips on the top before baking, if desired. Bake for 15-18 minutes, or until a tester comes out mostly clean.
Remove from oven and let cool for a few minutes, before removing to a wire rack to cool completely.