Turn the instant pot to sauté, add 1 tablespoons olive oil, and let heat for a minute or two. While the oil is heating, pat the chicken thighs dry with a paper towel and liberally season with salt and pepper on both sides. Add the chicken thighs to the oil, in a single layer (you may need to work in batches). Cook the chicken until golden on each side, about 3-4 minutes per side. Once golden, remove the chicken and place it on a plate.
If the inner pot is dry, add in an additional ½ tablespoon of olive oil and then add in the minced onion and diced peppers and sauté for 2-4 minutes, or until onions begin to soften. Once the onion has softened, add in the mushrooms and 1 tablespoon minced garlic and sauté for another 30-60 seconds.
Add in ½ cup dry white wine (or additional stock) and deglaze Instant Pot, scraping up any browned bits on the bottom of the pot. Let the wine cook off for 1 to 2 minutes. Turn the Instant Pot OFF by hitting cancel.
To the inner pot, add chicken stock (½ cup for 3 or 6-quart OR ¾ cup for 8-quart). Season with 2 teaspoons dried oregano, ¼ teaspoon crushed red pepper flakes, 2 tablespoons capers, ½ cup kalamata olives, and a pinch of salt and pepper. Stir to combine and then nestle the seared chicken thighs into the sauce. Sprinkle chicken with a bit of salt and pepper. Pour 28 ounces crushed tomatoes tomatoes over the chicken thighs and DO NOT STIR!
Close the lid on the pressure cooker, being sure the vent knob is placed towards the sealed position. Cook on high pressure for 7 minutes for boneless chicken thighs and 8 minutes for bone-in chicken thighs.
Once cook time has elapsed, allow pressure to release naturally for at least 10 minutes. After pressure has naturally released, open the Instant Pot and remove the cooked chicken to a new clean plate.
Turn the saute function back on the Instant Pot (hit cancel and then saute). Stir in the 1 tablespoon balsamic vinegar and then simmer the sauce to thicken, for 3-5 minutes. Taste and adjust the sauce with more salt and black pepper.
Serve chicken with sauce over noodles or rice topped with fresh basil and parmesan if desired.
Video
Notes
Wine: I recommend a dry white wine such as a sauvignon blanc or pinot grigio. If you do not drink, feel free to use additional chicken stock in place of the wine.Storage: Store leftovers in a sealed container in the refrigerator for up to 3 days. Alternatively, freeze it in a freezer-safe container, leaving ½-inch room for expansion, for 1-2 months.