Protein. One serving of these peanut butter overnight oats recipe has 11.4 g of protein. Fiber. Another nutrient we never get enough of, but that's abundant in chia seeds! Iron. Chia seeds are rich in iron, and are a great superfood to add to your diet if you're looking to increase your iron intake. Thickener. Chia seeds absorb the milk and thicken the mixutre.