Place whole tomatoes in a blender or food processor; process until pureed. Set aside.
Heat oil in a Dutch oven over mediumhigh heat. Add pork, and cook 5 minutes or until browned, stirring occasionally. Stir in onion, jalapeño pepper, and garlic; cook 3 to 5 minutes or until vegetables are tender. Add chili powder, cumin, and black pepper; cook 1 minute. Add reserved pureed tomatoes and diced tomatoes. Bring to a boil; reduce heat, and simmer, partially covered, 1 to 1 1/2 hours or until pork is tender, stirring occasionally.
Add chickpeas, hominy, chiles, and salt. Bring to a boil; cover, reduce heat, and simmer 30 minutes. Spoon into individual serving bowls. Top each serving with 1 tablespoon sour cream. Sprinkle 2 1/2 teaspoons avocado evenly over each serving.