Turn on the pressure cooker and press the SAUTE function, adjust to high. Pour in 2 tablespoons of olive oil and add the chopped onion, saut� until translucent. Add mushrooms and saut� for about 5 minutes.
Combine all the seasoning ingredients and season the chicken pieces.
Take out the saut�ed vegetables, pour in the remaining olive oil and add the chicken pieces in.
Quickly brown the meat. Turn OFF the saut� function and deglaze the pot with some of the chicken stock. Throw the onions and mushrooms back in, as well as the chicken. Add the rice and chicken broth and give everything a good stir.
Lock lid in position and close the vent. Press the MANUAL button (pressure cooking) and adjust the time to 3 minutes. When the cooking is finished, wait 7 minutes before releasing the pressure manually.
Stir in the butter and grated Parmesan. Taste it and add more seasoning if needed. Sprinkle with finely chopped chives (optional) and serve.