Mix meatballs: In a large bowl combine ground beef, breadcrumbs, egg, onion, garlic, cilantro, and spices. Mix gently with hands until just combined.
Shape meatballs: Roll mixture into 1–1 ½ inch balls. Place on a tray or plate.
Blend sauce: In a blender, mix tomato sauce, chipotle peppers, adobo sauce, brown sugar, oregano, cumin, chili powder, broth, and salt. Blend until smooth.
Assemble in crockpot: Lightly spray crockpot. Place meatballs inside. Pour chipotle sauce over the top. Stir gently to coat.
Cook: Cover and cook on low 5–6 hours or high 2–3 hours, until meatballs are cooked through.
Serve: Garnish with cilantro and lime wedges. Enjoy with rice, tortillas, or as a party appetizer.