In a large pot, cook the chopped bacon over medium heat until crisp, stirring often for even cooking. Remove the bacon to a paper towel-lined plate and set aside.
In the same pot, add the chopped onion and bell pepper. Cook until tender, stirring occasionally.
Add the ground beef and cook until browned. Drain off excess grease by tilting the pot and using a large spoon.
Stir in the kidney beans, pinto beans, black beans, fire-roasted tomatoes, tomato paste, jalapeño, beef stock, oregano, cumin, cocoa powder, kosher salt, black pepper, smoked paprika, ground coriander, chili powder, Worcestershire sauce, and garlic.
Add ¾ of the cooked bacon back into the pot and stir to combine.
Cook over medium-low heat for at least 45 minutes, stirring occasionally. For the best flavor, let the chili simmer all day or as long as possible, adding extra beef stock or water if needed to maintain the desired consistency.
Serve hot, garnished with sour cream, shredded cheese, chopped cilantro, and the remaining bacon. Enjoy!