Push sauté on Instant Pot, when hot add oil. Add onions, carrots, and celery and cook for five minutes, stirring often. Add garlic and stir for 30 seconds, then deglaze the pot with 1 cup of broth. Add the rest the broth, potatoes, chicken and sprigs of thyme on top. Lock on lid, set toggle to sealing. Pressure cook on high for ten minutes. Allow a 5-10 minute natural pressure release. Release pressure and remove lid. Remove sprigs of thyme.