Prepare the sauce: In a small bowl, whisk together the soy sauce, pineapple juice, brown sugar, barbecue sauce, apple cider vinegar, lemon (or lime) juice, and minced garlic until the brown sugar is fully dissolved and the sauce is well combined. (Optional: Marinate the chicken in the sauce overnight or for a few hours)
Add to Instant Pot: Place the raw chicken breasts or thighs into the bottom of the Instant Pot. Pour the prepared sauce evenly over the chicken, making sure each piece is well coated.
Pressure cook: Secure the lid and set the valve to sealing. Cook on high pressure for 10 minutes (for chicken breasts) or 12 minutes (for thighs). The Instant Pot will take a few minutes to come to pressure before the cooking time begins.
Natural release: Once the cooking cycle is complete, allow the pressure to release naturally for 5–10 minutes. After that, carefully turn the valve to venting to release any remaining pressure.
Remove chicken: Open the lid and transfer the cooked chicken to a plate or cutting board. You can shred it or slice it, depending on your preference.
Thicken the sauce: Turn the Instant Pot to sauté mode. In a small bowl, mix the cornstarch and water to create a smooth slurry. Slowly stir the cornstarch mixture into the sauce and let it simmer for 2–3 minutes, stirring frequently, until the sauce thickens.
Combine and serve: Return the chicken to the pot and toss it in the thickened sauce until fully coated. Serve hot over a bed of rice and spoon extra sauce over the top.