How to Make It
Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Place flour in a shallow dish. Dredge chicken in flour, turning to coat; shake off excess flour. Discard any remaining flour.
Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Add half of chicken; cook 3 to 4 minutes on each side or until browned. Transfer chicken to a 6-quart Instant Pot®. Repeat procedure with remaining chicken.
Add bell pepper, onion, and garlic to pan. Cook, stirring constantly, 4 minutes. Stir in wine. Cook 2 minutes, scraping pan to loosen browned bits. Stir in tomato purée. Add chicken, capers, and next 5 ingredients (through tomatoes) to cooker.
Close and lock the lid of the Instant Pot®. Turn the steam release handle to "Venting" position. Press [Slow Cook], and use [Adjust] to select "Less" mode. Press [-] or [+] to choose 3 hours 30 minutes cook time. Sprinkle with parsley before serving.