Add the milk, strawberries, maple syrup, vanilla, and salt to a blender. Blend on high speed until completely smooth, 20 to 30 seconds. Set aside.
Evenly divide the oats (½ cup each jar), chia seeds (1 tablespoon each jar), and chocolate (1 tablespoon each jar) between 4 lidded containers and stir to mix.
Evenly divide the strawberry milk mixture between the 4 containers. Stir again to mix, ensuring no dry ingredients are stuck on the bottom. Cover and refrigerate for at least 6 hours to set.
Before serving, top with ½ cup of yogurt and additional chocolate, if desired.
