Place all of the ingredients into a mixing bowl, and whisk to combine well.
Fill a jar or airtight container with the oat mixture, and allow to chill overnight in the fridge before serving.
Notes
Be sure to use old-fashioned oats. Also known as rolled oats, old-fashioned oats will hold their shape and texture better than quick oats.Finely chop nuts if added. That way, they won't overpower the overnight oats.Use a thick spread to give the oats a cookie dough-like texture. Peanut butter, nut butter, or seed butter is needed for a thicker texture. You can also use Nutella for added flavor and richness.Add some extra protein to your oats. Consider stirring in a scoop of protein powder.