Turn the Instant Pot on the saute setting.
Once hot, add the sausage and cook until brown. Drain. (you can also just brown the sausage in a skillet on the stovetop if you want it to go a bit faster)
Make sure there isn't any burnt sausage residue on the bottom of the pot before continuing. If so, DEGLASE the pot. You can do this by using a wooden spoon to scrape it up after adding the sausage and broth - BEFORE adding the remaining ingredients.
Add the sausage back to the pot along with the broth, tortellini, then the crushed tomatoes - IN THAT ORDER. DO NOT STIR.
Add the basil or baby spinach (if using), garlic, onions, salt, and pepper on top of the tomatoes. Do not stir.
Close the lid, set the valve to sealing.
Set to manual high pressure for 1 minute.
Allow for a 3-minute natural pressure release before doing a quick release of the remaining pressure.
Remove the lid, stir the soup.
Add the evaporated milk and parmesan cheese. Stir & serve.