Preheat the oven to 350°F (175°C). Line a muffin pan with paper liners or lightly grease the muffin cups.
Add the mashed banana, eggs, maple syrup, almond butter, almond milk, vanilla extract, protein powder, baking powder, and sea salt to a blender.
Blend until smooth and creamy, stopping to scrape down the sides if needed.
Stir in the chocolate chips, or pulse very briefly just until combined.
Divide the batter evenly between the prepared muffin cups, filling each about 3/4 full.
Sprinkle extra chocolate chips on top, if desired.
Bake for 18–22 minutes, or until the tops are set and a toothpick inserted into the center comes out mostly clean.
Cool in the pan for 5–10 minutes, then transfer the muffins to a wire rack to cool completely.