Divide the oats, chia seeds, and salt between two jars and stir.
Add the milk, Greek yogurt, maple syrup, and vanilla to each jar.
Stir well, scraping the bottom and sides, until no dry oats remain.
Let rest 10 to 15 minutes, then stir again.
Cover and refrigerate for at least 6 hours or overnight.
Stir, loosen with a splash of milk if needed, add toppings, and serve.