Preheat the oven to 355°F (180°C) and line a muffin pan with 12 muffin liners.
In a medium bowl, whisk together the flour, oats, baking powder, baking soda, and salt.
In a bowl, add the white sugar, brown sugar, and eggs. Whisk until well combined. Stir in the butter, oil, vanilla extract, grated zucchini, and milk.
Add the wet ingredients to the dry ones and mix just until no dry ingredients are left.
Fold in the chocolate chips.
Divide the batter evenly between muffin liners and bake for 27-30 minutes or until a toothpick inserted into the center of a muffin comes out clean and the tops are golden.
Remove the muffins onto a cooling rack to cool them down to room temperature before serving.