Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners or grease it lightly.
In a large mixing bowl, combine the Kodiak Cakes mix, brown sugar, baking powder, baking soda, and salt.
In a separate bowl, whisk together the milk, egg, and vegetable oil until well blended.
Pour the wet ingredients into the dry ingredients and stir until just combined.
Gently fold in the chocolate chips. Do not overmix; a few lumps are okay.
Divide the batter evenly among the muffin cups, filling each about ¾ full.
Bake for 15-18 minutes or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.