Add oil to 6 Quart Instant Pot and select high Sauté setting. Allow oil to heat for 2 minutes. Sprinkle chicken with salt and pepper, then add chicken to pot in even layer and cook 6 to 7 minutes or until chicken begins to brown, stirring occasionally.

Meanwhile, in small bowl, stir together garlic, 1/2 cup broth, tomato sauce, brown sugar, vinegar, soy sauce and ginger.

Add bell pepper, yellow onion, pineapple and broth mixture to pot and stir to combine. Secure lid and set Pressure Release to Sealing. Press Cancel button to reset cooking program. Select Pressure Cook or Manual Setting and set cooking time for 1 minute at low pressure (pot will take about 10 minutes to come to pressure before cooking time begins).

When cooking time ends, perform quick pressure release by moving Pressure Release to Venting. While pressure is releasing, whisk cornstarch and remaining 1 tablespoon broth in small bowl until smooth.

Open pot and stir in cornstarch mixture. Press Cancel button to reset cooking program. Select Sauté setting and cook for 1 minute, stirring constantly. Sauce should thicken during this time.

Divide rice between 4 plates and divide chicken mixture over rice. Serve garnished with green onions.