Preheat the oven to 375 degrees F. Line a standard 12-cup muffin pan with paper liners.
Combine flour, baking powder, baking soda and salt in a large bowl and whisk to blend evenly.
Combine Greek yogurt, maple syrup, oil, eggs, vanilla and milk in another large bowl and whisk until smooth and evenly combined.
Add the dry ingredients to the bowl with the wet ingredients and stir together gently with a large spatula until mostly incorporated.
Before all of the flour is combined, add the chocolate chips and fold them through until evenly distributed.
Use a large cookie scoop or two spoons to divide batter evenly into the prepared muffin liners, filling them so they are all the way full.
Sprinkle extra chocolate chips and a generous sprinkle of coarse sugar over top.
Bake for 15-20 minutes until golden on top and a skewer inserted into the center comes out clean.
Remove the pan from the oven and let cool for 5 minutes, then transfer muffins individually to a wire rack to cool.
