Wash and pat chicken dry, then season with salt and pepper (and garlic).
Set the Instant Pot on the Sauté setting to melt the butter with oil.
Add chicken in batches to brown on each side for about 5 minutes.
Put all chicken pieces back in the pot and add onion. Stir for about 2 minutes.
Add carrots, celery and turn over.
Sprinkle flour and stir in, cooking for 2 minutes.
Add broth (bouillon) and marjoram.
Switch from Sauté setting to Pressure cooking
Cover the Instant Pot and cook for 10 minutes.
Release pressure and transfer the chicken to a platter or dish.
Garnish with chives and parsley.
Skim fat from the juices and either serve separately, or spoon over chicken.