In a small mason jar or container, combine all of the ingredients from the first list. Stir thoroughly to make sure the oats are fully coated in the yogurt and nut milk mixture.
To make the blueberry chia compote, place all the compote ingredients into a small saucepan over medium heat. As the blueberries begin to burst, use a wooden spoon to gently mash them. Increase the heat to medium-high and bring the mixture to a gentle boil. Cook for about 5 to 8 minutes, stirring frequently, until it thickens. Let it cool completely, then taste and adjust sweetness if needed.
Add 1 tablespoon of the cooled blueberry chia compote to the oat mixture in your container and stir to combine.
Refrigerate the jar or container overnight or for a minimum of 4 hours to allow the oats to soften and absorb the flavors.
When ready to serve, top with an additional tablespoon of the blueberry chia compote, a few fresh blueberries, and a sprinkle of crumbled walnuts.