Add the chicken thighs to a large bowl. Add 1/2 teaspoon of smoked paprika, 1/2 teaspoon of cayenne pepper, 1/2 teaspoon of dried oregano, the onion powder, garlic powder, salt, and pepper. Use your hands to rub the spices and seasonings evenly all over the chicken thighs. You may adjust the quantity of spices, adding more or less to suit your personal taste.
Add the olive oil to the instant pot. Set to sauté. Once the oil is hot, place the chicken thighs in the pan skin side down. Leave the chicken to cook for 4-5 minutes on the first side until golden and crisp. Turn the chicken pieces over and cook on the second side for 4-5 minutes or until golden brown all over.
Add the chicken stock, tomato sauce, and remaining herbs and spices to the instant pot. You may use an alternative stock if preferred, such as vegetable. Stir gently to mix. Place the lid securely on the instant pot and ensure that it is set to sealing. Set the pressure to high and set the time for 15 minutes. After this time, quick release any remaining pressure.
Once safe to do so, remove the lid from the instant pot and check the chicken is completely cooked through. Add the cauliflower rice to the instant pot and set to sauté. Heat the rice through in the pan juices for 3-4 minutes or until tender. Divide the chicken and rice between 4 serving plates or bowls, accompanied by your preferred Keto sides.