Finely chop the onion and green onion.
Cut the chicken breast into bite-sized pieces.
Add olive oil to a pan and sauté the onion and green onion.
Add the chicken breast and cook until done.
Add spicy chicken sauce and stir-fry evenly.
Scoop soft tofu with a spoon and place it in the pan; mix lightly.
Turn off the heat and transfer to a gratin dish.
Top with mozzarella cheese and bake in the oven at 200°C for 8 minutes to melt the cheese.