In a small bowl, combine the chicken stock, sugar and teriyaki sauce. In a large frying pan, heat the vegetable oil over medium-high heat. Add the onions and cook until softened and starting to brown.Pour the chicken stock mixture into the pan and simmer for 3-4 minutes or until thickened slightly. Carefully lay each sliced pork cutlet into each half of the pan. Drizzle the pork and onions with the whisked eggs. Cover with a lid and cook for about 2 minutes or until the egg is just set.