In a 5- to 6-qt slow cooker, stir together tomatoes (and their juices), chili powder, oregano, cumin, 1 cup water, and ¼ tsp each salt and pepper.  Stir in wheat berries, onion, poblano, and garlic. Cook, covered, until wheat berries are tender but still a bit chewy, 7 to 8 hours on Low or 4 to 5 hours on High. Ten minutes before serving, gently stir in beans, corn, and chicken and cook until heated through. Serve topped with cilantro, Cotija, and lime wedges if desired.