Turn on the sauté function on a 6-quart Instant Pot and pour olive oil into the inner pot.

Add sausage, onion, Italian seasoning, garlic powder, salt, and pepper to the inner pot.

Sauté until sausage is brown and onions are translucent in color, about 6-8 minutes.

Turn off the sauté function and add tortellini, chicken stock, spinach, and tomatoes.

Lock the lid onto the instant pot, check that the steam valve is set to seal, and set the instant pot on low pressure for 2 minutes.

When the 2-minute timer ends, do a quick release on the steam valve and remove the lid.

Serve hot with grated parmesan cheese, if desired.