Start by cutting the chicken breasts into bite-sized pieces for even cooking. Chop the green bell pepper into squares and cut the yellow onion into wedges.
In a mixing bowl, whisk together the chicken stock, pineapple juice, ketchup, soy sauce, rice vinegar, honey, and pepper. This will be your flavorful sauce.
Set your pressure cooker to the sauté function. Add a drizzle of oil and toss in the onion and green bell pepper. Sauté for about 2-3 minutes until they start to soften.
Add the chicken pieces to the pot, followed by the prepared sauce. Stir well to coat the chicken and vegetables.
Seal the pressure cooker lid and set it to cook on high pressure for 8 minutes. Once the cooking time is up, allow for a natural release for 5 minutes before doing a quick release for any remaining pressure.
In a small bowl, mix the cornstarch and cold water until smooth. Once the pressure is released, switch the cooker back to the sauté function. Stir in the cornstarch mixture and simmer for a few minutes until the sauce thickens.
Serve the sweet and sour chicken over a bed of rice or noodles, drizzling extra sauce on top. Garnish with sesame seeds or sliced green onions if desired. Dig in and savor every bite!