Set the Instant pot to saute and when hot, add the olive oil, onions and garlic, saute for a minute or so. Then add the meatballs, italian seasonings, salt and chilli flakes. Saute for about 2 minutes.
Add the water, tomato paste and pasta into the inner pot, mix well. Put the lid on and set it to sealing. Choose pressure cook and set it for 3 minutes.
When done, gradually release the steam. Be careful of any foam or liquid squirting from the valve. Stir in cream cheese, parmesan and spinach, this will wilt in the heat. Serve hot.