Chop the onion and garlic. Turn the Instant Pot to Saute mode and allow it to heat up before adding the olive oil. Add the onion and garlic and cook until the onions are translucent, about 3-4 minutes.
Add the chicken broth, seasonings, diced tomatoes, tomato sauce and the frozen tortellini and stir.
Close the lid, turn the venting knob to “sealing” and cook on HIGH pressure for 5 minutes before quickly releasing the pressure.
Add the heavy cream/milk and the spinach and stir until the spinach is wilted.