Preheat oven to 375 degrees F and spray muffin tin with cooking spray. Set aside.
In a large bowl, add Greek yogurt, milk, maple syrup, oil, egg, vanilla, baking powder, and baking soda. Whisk well to combine.
Add flour and gently stir until well incorporated. Do not over mix otherwise muffins will be tough.
Add almost all of chocolate chips, reserving some for the tops, and give a few more gentle stirs.
Using large cookie scoop, divide batter between 12 openings of a muffin tin and decorate with remaining chocolate chips, pressing on them lightly.
Bake for 20-22 minutes or until a toothpick inserted in the center comes out clean.
Remove from the oven, let muffins cool for about 5 minutes and transfer to a cooling rack to cool off a bit more.