Cut the thawed chicken breast into bite-sized pieces.
Heat a spoonful of olive oil in a pan, add the chicken breast and cook until golden. Then add the onion and sauté together.
Add the prepared sauce (3 soy sauce, 2.5-3 water, 1 allulose, 1 mirin), and simmer over medium-low heat.
Once the sauce has thickened a bit, pour in a beaten egg, cover with a lid, and cook for 2-3 minutes.
Serve over rice.