Place a large pot over medium heat and add the olive oil.
When the pot is hot and the oil is shimmering, add the ground beef, bell pepper, onion, chili powder, garlic powder, cumin, oregano, salt, cocoa, cinnamon, and pepper.
When the meat has cooked through and the veggies are becoming tender, create a well in the center of the pot and add the tomato paste.
Cook the tomato paste, stirring, until browned and a film is appearing on the bottom of the pot.
Pour in the stock, scraping the film off the bottom of the pot with your spoon, to bring it up into the liquid.
Transfer the mixture to a slow cooker (if using) and add the crushed tomatoes, beans, and corn.
Taste, add sugar if needed, and allow to simmer over very low heat (stirring occasionally), until the vegetables are tender (about 20 minutes, or up to 6 hours).*
Notes
*If the chili becomes too thick, add water to dilute.