Cut the chicken thighs into thin, bite-sized pieces about ½-inch thick.
Mix pineapple juice, banana ketchup, sugar, garlic powder, and salt in a bowl until sugar dissolves completely.
Add chicken pieces to the marinade and mix well, making sure each piece is coated. Place in a container and refrigerate for 4-8 hours.
Remove marinated chicken from the refrigerator 15 minutes before cooking.
Place chicken and marinade in a pan over medium heat. Add 1 cup water and bring to a boil.
Lower heat, cover the pan, and simmer for 15-20 minutes until chicken is tender.
Once liquid is mostly absorbed, add cooking oil and increase heat to medium-high.
Cook for 5-7 minutes, turning chicken pieces occasionally, until they turn golden brown and slightly charred.
Turn off heat and let rest for 2-3 minutes before serving.
Serve hot with garlic rice and sunny-side-up egg for a complete breakfast meal.
Note: Don't marinate longer than overnight as the pineapple juice can make the chicken too soft.