Heat the Instant Pot on sauté mode. Add the cooking oil. Once hot, add the onion and bell pepper, sauté until softened, about 3 minutes.
Add the garlic and ground beef and crumble while cooking, until browned, about 5 minutes.
Turn off saute mode.
Pour in the whole can of tomatoes, tomato paste, chili powder, cumin, and salt. Stir to combine. Remove any browned bits from the bottom of the pot.
Pour in the beef broth. Then pour the macaroni on top. Don’t stir, but push the noodles down so they are submerged.
Secure the lid and set the vent to sealing (if necessary for your model).
Set to cook on high pressure for 2 minutes. When the time is up, allow the pressure to release naturally for 10 minutes. Release any remaining pressure. Remove the lid and stir.
Sprinkle on the cheese and stir until melted. The pasta will thicken as it sits, so if it’s too soupy, let it sit for 5 minutes before serving.