Press the Sauté button on the Instant Pot® and heat ghee. Add onion and green pepper and sauté for 3–5 minutes until onions are translucent. Stir in garlic. Add the chicken breast skin-side down and brown for 3–4 minutes. Sprinkle the diced tomato over the chicken.
In a medium bowl, whisk together tomato sauce, paprika, and chicken broth. Pour over chicken. Lock lid.
Press the Poultry button and cook for the default time of 15 minutes.
When timer beeps, let pressure release naturally for 10 minutes. Quick-release any additional pressure until float valve drops and then unlock lid. Check the chicken using a meat thermometer to ensure the internal temperature is at least 165°F. Transfer chicken to a serving platter.
Whisk flour and sour cream into the juices in the Instant Pot®. Press the Sauté button, press the Adjust button to change the temperature to Less, and simmer unlidded for 5 minutes until sauce thickens. Season with salt and pepper. Pour sauce over chicken and serve warm.