Set pot to saute, add olive oil, Italian seasoning and garlic powder.
Cube steak into bite size pieces and sear on all sides, then turn pot off. Pour in 1 cup of your broth and scrape stuck on pieces of meat off the bottom of the pot to deglaze.
Pour in remaining broth, potatoes, carrots, onions, celery and remaining seasonings. Stir
Put on pressure cooking lid (that isn't attached), press pressure button, high setting, for 4 minutes cook time.
Allow to naturally release pressure for 1 minute, then quick release.
Remove lid and add mushrooms. Put lid on ajar for 5 minutes to allow them to soften. If you want to thicken broth you can set to saute again and whisk some of the hot broth with 3 tbsp cornstarch in a bowl until smooth. Stir that in, allow to bubble and thicken.