Set the Instant Pot to the Sauté setting. Add the ground beef and onion and cook until the beef has browned and the onion is translucent, about 3 to 5 minutes. Drain away excess drippings from the ground beef.
Stir in the tomato paste, chili powder, Stone House Seasoning, cumin, and the cocoa powder. Next, stir in the beef stock, crushed tomatoes, kidney beans, and black beans.
Set the Instant Pot to 18 minutes at High Pressure. When the chili has finished cooking, use an oven mitt and carefully use the quick-release method to release the pressure according to manufacturer’s directions.
Serve the Instant Pot Chili with toppings as desired.