Add rolled oats to a clean glass jar or airtight container.
Pour milk over the oats until fully covered.
Add chia seeds and sweetener such as honey or maple syrup.
Stir the mixture well so the oats absorb the liquid evenly.
Add your chosen flavor ingredients or fruit.
Mix gently until everything is evenly combined.
Seal the jar with a tight lid.
Place the jar in the refrigerator overnight or for at least 6 hours.
In the morning, stir the oats again before serving.
Enjoy directly from the jar or transfer to a bowl.