Turn your Instant Pot to the sauté function. Add some olive oil to the Instant Pot and saute the onions until translucent and soft.
Add the beef into the pot. Break apart the meat with a wooden spoon and allow it to brown completely.
Once the meat is browned, add the chicken stock into the pot and use a wooden spoon to scrape up the browned bits on the bottom of the pot. This is an important step as you don’t want to cause a burn notice effect later.
Add the tomato sauce into the pot, then the shells, then the Italian seasoning, then salt to taste in that order.
Set Instant Pot to HIGH for 5 minutes. Once the pasta is done cooking, do an instant Release. Open the lid to the Instant Pot and add in the cream and the parmesan cheese. Stir to combine. Enjoy!