Add 1/2 cup of the pineapple juice, teriyaki sauce, water and cornstarch to a skillet. Us a whisk to stir until the cornstarch is fully incorporated.
Add the brown sugar and cook over medium heat for 3 minutes, or until the sauce is thick and bubbly.
Add the chicken and pineapple tidbits. Stir to coat. Cook over medium-low heat for 5 minutes, or until the chicken is heated through.
Serve over rice.