Add rolled oats, chia seeds, cinnamon, and salt to a 12–16-ounce jar or food-storage container.
Stir briefly to distribute the chia seeds.
Add Greek yogurt and almond butter.
Add maple syrup and vanilla.
Pour in the milk.
Stir thoroughly until the yogurt and almond butter are mostly incorporated.
Check the bottom and corners for dry oats.
Let the mixture stand for approximately 5 minutes.
Stir again to break apart any chia clumps.
Cover tightly.
Refrigerate for at least 6 hours or overnight.
Stir thoroughly in the morning.
Add a splash of milk if a thinner consistency is desired.
Top with fruit, nuts, or additional almond butter.
Serve cold or gently warmed.