- Press saute button (adjust to less if your Instant Pot runs hot). When the Instant Pot is hot add oil and diced onions. Saute onions for about 3-4 minutes until lightly browned. Add minced garlic and saute for 30 more seconds. 
- Add ground beef, chili powder, ground cumin, and oregano. Break up the meat into small pieces and saute until browned, about 4 minutes. 
- In a small bowl combine beef broth, tomato paste, and unsweetened cocoa powder until dissolved. Pour mixture into the Instant Pot to deglaze the pot. Use a spatula to scrape the bottom of the pot. 
- Add beans and stir until everything is combined. Then add tomatoes on top but don't stir. Layering the ingredients prevents getting the burn error.  
- Cover and cook for 10 minutes at high pressure. Natural release for 10 minutes and then quick release the remaining pressure. Remove the lid and stir until everything is combined. 
- If you want to add corn: Press the Saute button and add the sweet corn. Let simmer for a few more minutes until the corn is cooked through. 
- Season to taste with salt and black pepper and serve topped with sour cream and cheese.