Using your hands or the lid of a mason jar, form the mashed potatoes (this is a great way to used left over mashed potatoes!) into two rounds. Place the potato pancakes into the skillet of olive oil and allow them to fry for two minutes. Flip the potato pancakes and add the shredded Swiss chard to the skillet. Sprinkle the swiss chard with sea salt and pepper. Cook for an additional two minutes.