Add rolled oats, milk, yogurt, chia seeds, honey or maple syrup, vanilla extract, and salt to a small jar or airtight container.
Stir thoroughly until the yogurt is incorporated and the oats and chia seeds are evenly distributed.
Cover and refrigerate for at least 6 hours or overnight.
Stir the oats before serving. Add a splash of milk if they are too thick.
Add desired toppings and serve cold, or transfer to a microwave-safe bowl and warm gently.
Store covered in the refrigerator and use within 3 to 4 days.