Turn on your Instant Pot and select the 'Saute' function on high.
Add olive oil, onion and sausage and saute until browned.
Add garlic and saute for an additional 1-2 minutes.
Select the 'Cancel' button to turn off the Instant Pot and reset the cooking function.
Add pasta sauce, garlic pepper, basil, red pepper flakes, Italian seasoning, salt, beef broth, water and pasta shells. NOTE: When you add the pasta shells, be sure to add them in a criss-cross motion. Doing so will help the pasta shells from sticking together. Also, as you are adding the shells, try to press as much of the shells under the water as possible.
Select the 'Pressure Cook' function and cook on high for 4 minutes.
Once the timer beeps, quick release all pressure then carefully remove the lid.
Stir contents to break up the pasta and combine all ingredients well.
Add Parmesan cheese and stir again until contents are well combined.
Serve, top with mozzarella cheese and enjoy!!