In a bowl, whisk together pineapple juice, soy sauce, brown sugar, ketchup, chicken broth, garlic, ginger, and rice vinegar until sugar is dissolved.

Pour exactly HALF of this marinade into a small saucepan and set aside for the glaze.

Place the bite-sized chicken pieces in a bag or bowl and pour the remaining half of the marinade over them. Marinate in the fridge for at least 30 minutes (up to 4 hours).

To make the glaze, bring the reserved marinade in the small saucepan to a boil over medium heat. Stir in the cornstarch slurry and simmer for 2-3 minutes until thick and glossy. Remove from heat.

Heat cooking oil in a large skillet over medium-high heat. Remove chicken from marinade (discard used marinade) and add to the skillet in a single layer.

Cook undisturbed for 3-4 minutes to sear, then flip and cook another 3-4 minutes until cooked through and charred.

Pour the thickened glaze over the cooked chicken in the skillet. Toss for 1 minute until every piece is heavily coated and sticky.

Remove from heat and serve immediately over hot rice.