Set the Instant Pot to sauté mode.
Add the olive oil and sauté the chicken until browned on all sides.
Add the onion, celery, carrots, mushrooms, and garlic. Sauté for 3-4 minutes until the vegetables are slightly softened.
Add the barley, dried thyme, dried rosemary, salt, and black pepper. Stir to combine.
Pour in the chicken broth and give everything a good stir.
Lock the lid and set the Instant Pot to Manual mode for 15 minutes.
Once the cooking time is complete, allow the pressure to release naturally for 10 minutes, then do a quick release.
Remove the chicken breasts from the soup and shred them using two forks.
Return the shredded chicken to the pot and stir to combine.
Serve hot and enjoy!
