Add rolled oats, protein powder, and chia seeds to a bowl or jar.

Pour in the milk and Greek yogurt.

Stir well until the protein powder is fully dissolved and mixture is combined.

Add honey or maple syrup if using and mix again.

Cover the container with a lid.

Refrigerate overnight or for at least 6 hours.

Stir before eating and add desired toppings.

Serve cold or warm slightly if preferred.