In a 1-quart container or medium bowl, whisk together oat milk, maple syrup, vanilla paste or extract (if using), and salt until well combined.
Add oats and chia seeds and stir to combine.
Refrigerate until oats have softened and thickened, at least 8 hours and up to 24 hours. Sweeten with additional maple syrup as needed and serve with fresh fruit, if desired.
