Coat slow-cooker bowl with nonstick cooking spray. Season pork with chili powder, oregano, cumin and 1/2 tsp of the salt. Place in slow cooker; add onion, garlic, sweet potatoes and green pepper, in that order. Pour broth over top.
Cover and cook on HIGH for 6 hours or LOW for 8 hours.
Add remaining 1/2 tsp salt 45 minutes before end of cooking time; drop cornbread batter (see below) in heaping tbsp on top. If cooking on LOW, add 15 minutes.
Cornbread: In a large bowl, whisk together cornmeal, flour, sugar, baking powder and salt. Cut in butter until mixture resembles coarse meal. Stir in milk until just moistened; fold in cilantro.