Preheat: Set the Instant Pot to "saute" setting and spray the insert with cooking spray.
Prepare beef: Add in the ground beef and cook until it begins to brown - breaking it into crumbles with a wooden spoon.
Create sauce: Add the onion, garlic, salt and pepper, red pepper flakes, brown sugar, and Italian seasoning; stir well. Next, stir in the chicken broth and heavy cream.
Add pasta: Press "cancel" on the Instant Pot. Add the pasta (do not stir!). If the pasta is not submerged in the sauce, add water -up to 1/3 cup- to ensure the pasta is submerged. Finally, pour the passata over the past (do not stir!) and close the lid.
Cook: Turn the sealing valve on the Instant Pot to the "seal" position, and cook on high pressure for 5 minutes. Note: it will take about 10 minutes for the instant pot to come to pressure.
Finish: When cooking time is complete, release the steam valve and press "cancel". Once pressure has been released, remove the lid and stir in 1 1/2 cups of mozzarella cheese. Top the ziti with the remaining mozzarella and let it stand for about 10 minutes.
Serve: Garnish with fresh basil and serve warm!