Line slow cooker with foil collar and sling. Spray with cooking spray.
Saute onion and bell pepper in vegetable oil for 3-4 minutes. Add garlic and continue cooking for 1-2 more minutes.
Stir in tomato paste, cumin, oregano and chili powder and continue cooking for 2 minutes more.
Mash bread, beans, and milk together in a large bowl using your hands.
Combine bread mixture and onion mixture with ground beef, cheese, corn, eggs, green chiles, cilantro, salt and pepper using your hands.
Press mixture into an even layer in slow cooker.
Brush with 1/4 cup of barbecue sauce.
Cover and cook on low for 4 hours or until meatloaf is tender and cooked through.
Heat broiler. Transfer meatloaf, using foil sling, to a rimmed baking sheet. Let juices drain into the slow cooker.
Push foil away from meatloaf and brush with remaining 1/4 cup barbeque sauce.
Broil for 3-5 minutes until sauce is bubbling and beginning to caramelize.
Let meatloaf rest for 15 minutes before serving.