Place the garlic, cocoa powder, chili powder, cumin, cayenne pepper, and Mexican oregano in a small bowl. Season with salt and black pepper to taste, and stir to combine.
Rub the seasoning mixture all over the pork and place in a 5 or 6-quart (5 or 6-liter) slow cooker pot.
Place the red onion, green chilies, tomato paste, diced tomatoes, red kidney beans, and black beans around the pork. Pour over the liquid smoke and chicken stock and stir to combine all the ingredients.
Cover the pot and cook the pork on high for 4 hours, or on low for 8 hours. Do not remove the lid while cooking.
When the cooking time has finished, remove the slow cooker lid and use two forks to pull the pork apart. Mix everything together in the pot and leave the pulled pork to rest in the juices for 10-15 minutes to absorb more flavor.
Place a portion of pulled pork chili into a bowl and top with Mexican cheese, chopped red onion, and/or chopped fresh cilantro. Enjoy!