Once the pot reads "hot", add the olive oil, and brown chicken thighs on both sides, about 3-4 minutes per side. Remove to plate.
In the now empty pot, add onion and peppers. Cook until vegetables begin to soften, about 4-5 minutes.
Stir in the garlic, and cook, stirring the entire time, for 30 seconds.
Add the chicken broth and scrape up any browned bits from the bottom of the pot.
Layer in the crushed tomatoes, diced tomatoes, Italian seasoning, garlic powder, and salt. Do not stir.
Return chicken to pot, nestling into sauce.
Close and lock the lid and set pressure release valve to sealing position. Select manual high pressure, and adjust the cooking time to 10 minutes. It should take about 10-15 minutes to come to pressure.
When cooking time has finished, let the pressure release naturally for 15 minutes.
Carefully release remaining pressure.
Unlock the lid, and remove the chicken thighs. The chicken should be cooked to 165F.
Give the sauce a good stir.
Serve chicken and sauce over pasta, garnished with parsley if desired.
Notes
Chicken thighs: Use bone-in thighs or chicken breasts if preferred. If using a different type of chicken, you'll need to adjust the cooking time accordingly.
Bell peppers: Feel free to use whatever color peppers you like.
Chicken broth: I like to use reduced-sodium broth to better control the salt level in the dish. You can also use chicken stock or vegetable broth.
Diced tomatoes: Diced tomatoes with olive oil and garlic add even more flavor to the dish.