Prepare chicken, ketchup, and onion in a 2:1:1 ratio.
Cut the chicken into bite-sized pieces.
Finely chop the onion.
Add cooking oil to a pan and stir-fry the chicken.
When the chicken is halfway cooked, add the onion and stir-fry together.
Add ketchup and stir-fry well until mixed evenly.
Once the ingredients are cooked, turn off the heat and plate the dish.