Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease the cups.
In a large mixing bowl, whisk together Kodiak Cakes Power Cakes mix, cocoa powder, sugar, baking powder, and salt until well combined.
In a separate bowl, beat the eggs, then add milk, vegetable oil, and vanilla extract. Mix until smooth.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Do not overmix; the batter should be slightly lumpy.
Fold in the semi-sweet chocolate chips evenly into the batter.
Divide the batter evenly among the 12 muffin cups, filling each about 3/4 full.
Bake in the preheated oven for 16 to 18 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove the muffins from the oven and allow them to cool in the pan for 5 minutes.
Transfer the muffins to a wire rack to cool completely before serving.