Cut the chicken into bite-sized pieces.
Soak the rice cakes in lukewarm water.
Slice the onion and green onion thinly.
Heat cooking oil in a pan and stir-fry the chicken.
When the chicken is halfway cooked, add the rice cakes, onion, and green onion and stir-fry together.
Add gochujang (Korean red chili paste), soy sauce, and sugar, and mix well.
Top with mozzarella cheese and simmer until the cheese is melted.