Turn Instant Pot to Saute function.
Once heated, add in oil. Brown Italian Sausage until almost no longer pink, breaking up sausage as it cooks.
Add in onions, carrots, and garlic and saute for 2-3 minutes longer.
Add stock, tomatoes, tomato sauce, and pasta to Instant Pot.
Place lid on Instant Pot and turn knob to sealed. Cook on High Pressure for 4 minutes.
Once cook time has elapsed, allow pressure to release naturally for 5 minutes. Then do a quick release for any remaining pressure.
Stir in spinach to soup and let just wilt.
Serve soup with cheese.