Place all ingredients except the nuts in a container and stir until well combined. Seal with a lid and place in the fridge overnight (or at least a couple hours).
Bring out of the fridge in the morning and stir. You'll notice that the oats soak up a lot of the liquid so you may want to add a little more almond milk before serving. Top oats with chopped nuts and serve.
Notes
Almond milk: Feel free to use any dairy or non-dairy milk of choice.
Maple syrup: Honey or another natural liquid sweetener will work here as well. If you want to reduce the sugar in this recipe, feel free to use a sugar alternative like stevia or monk fruit.
Want to add protein? Add a scoop of protein powder or 1/4 cup Greek yogurt and reduce the milk to 1/2 cup.