DO AHEAD: Pancakes can be made ahead. Reheat by popping them into the toaster, or turn oven to 300F/150C and bake covered in foil for 20 minutes.
Chia seeds take time to absorb liquid, which is why I’ve recommended waiting 10 minutes for the chia to absorb and thicken the batter. If you notice the batter is thin at first, this is why. If batter looks too thick after 10 minutes, you can add splashes more oat milk to thin. I found 1.5 cups oat milk in total the perfect amount.
I recommend using a non-stick skillet to flip your pancakes. I started by adding 1/2 tsp coconut oil to season. Both these recommendations help to stop your pancake batter from sticking to the pan.