Combine oats, milk, pumpkin puree, spices, maple syrup, and vanilla extract in a mixing bowl. Stir thoroughly until all ingredients are evenly incorporated and the mixture looks creamy with a speckled appearance from the spices.
Pour the mixture into a jar or container with a lid, smoothing out the surface gently with the back of a spoon.
Seal the container tightly and place it in the refrigerator overnight, allowing the oats to soak and absorb the flavors until they become tender and creamy.
In the morning, remove the jar from the fridge and give it a good stir. The oats should be thickened and creamy, with a rich pumpkin aroma wafting upward.
If desired, warm the oats slightly in the microwave or enjoy chilled straight from the fridge. Serve in bowls with additional toppings like nuts or fruits for extra texture.