Combine the oats and chia seeds in a large bowl. Pour in the almond milk and maple syrup, stirring until everything is well mixed. This will be the base of your overnight oats.
Cover the bowl with a lid or plastic wrap. Place it in the refrigerator to let the oats soak up all the flavors and soften as they sit overnight, ensuring a creamy texture.
In the morning, give the oats a good stir. Fold in most of the blueberries, reserving a few for a colorful garnish. Evenly distribute the mixture into serving jars or bowls.
Add a final touch by sprinkling the remaining blueberries on top. If you like, you can also add a handful of nuts or a sprinkle of coconut flakes for extra crunch and flavor.