Set the Instant Pot to "Sauté" on high. Pour the oil into the pot and heat until shimmery. Add the onion and cook, stirring, for 4-5 minutes, until softened, stirring in the garlic during the last 30-60 seconds of cooking.
Add ground beef to the pot and cook until no more pink is visible. Drain excess fat if necessary. (Tip: Place a metal colander over a large bowl and drain the meat. Then discard the cooled grease into the trash later.)
Stir in the kidney beans, black beans, tomato sauce, broth, tomato paste, diced tomatoes, chili powder, cumin, cayenne, salt, and pepper.
Lock and seal the lid. Cook at high pressure for 7 minutes, and then quick release the pressure.
Taste and adjust salt and pepper amounts. Serve topped with your favorite chili toppings, like shredded cheese, sour cream, avocado, green onion, or any other favorite toppings.