Cut the chicken into bite-sized pieces.
Slice the onion and green onion thinly.
Heat some cooking oil in a pan and sauté the chicken.
When the chicken is half cooked, add the onion and green onion and stir-fry together.
Add soy sauce, sugar, minced garlic, and pepper, and mix well.
Continue to cook until the chicken is fully done.
Serve the sautéed chicken and vegetables over rice.