Combine garlic, cocoa powder, chili powder, cumin, cayenne pepper, oregano, salt and black pepper in a small bowl.
Rub pork roast with seasoning mixture on all sides and place in the crock of a 5 or 6-quart slow cooker.
Arrange the onion, chilies, tomatoes and beans around the roast around the pork. Pour the tomato paste, liquid smoke and chicken broth on top. Stir the ingredients on each side of the pork to combine.
Cover and cook on high for 4 hours, or on low for 8. Do not remove lid while cooking.
When cook time is complete, shred the pork with two forks. Allow the pork to rest in the juices for about 10-15 minutes to absorb more flavor.