Preheat the oven to 350°F (175°C). Lightly grease a muffin tin or line with paper liners.
In a large bowl, mix rolled oats, baking powder, cinnamon, and salt.
In a separate bowl, whisk together eggs, milk, maple syrup, melted butter, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until well combined.
Fold in the chocolate chips evenly throughout the mixture.
Divide the mixture evenly among the muffin cups, filling each about three-quarters full.
Bake for 20–25 minutes, or until the tops are set and lightly golden.
Remove from the oven and let cool slightly before removing from the pan.