Drain tomatoes and keep liquid in a bowl.
Chop tomatoes into large chunks.
Heat oil in a large stew pot over medium-high heat.
Add onions and garlic; saute for 2-3 minutes.
Add beef and pork; stir frequently until meat is fully browned and onion is soft.
Combine chili powder and flour, mix until incorporated; add to meat mixture and stir until equally covered.
Add tomatoes and stir until combined.
Add remaining spices, simmer slowly for about 2 hours; stirring often.
Add unsweetened chocolate 1 hour into cooking; stir until chocolate is melted.
Serve hot with cheddar cheese, cream cheese, and tortilla chips.