Set the Instant Pot to Sauté and melt the butter.
Add the chopped onion, sliced red and green bell peppers, and minced garlic; sauté until softened, about 3–4 minutes.
Turn off Sauté. Add the chicken pieces to the pot, then pour in the soy sauce and rice vinegar. Add the bay leaves, kosher salt, and black pepper.
Close the lid and set the valve to SEALING. Cook on High pressure for 15 minutes.
When the cook time ends, let the pressure sit for 5 minutes, then perform a quick release to remove remaining steam.
Remove the lid, stir the chicken and vegetables, then select Sauté. Turn the chicken pieces over and simmer in the sauce, stirring occasionally, for about 5–8 minutes to reduce the sauce slightly.
Remove and discard the bay leaves. Serve the chicken over rice.