- In a large slow cooker, stir together ketchup, Coca-cola™, grated onion, Worcestershire sauce, and spices.
- Add chicken pieces, which should be mostly covered by liquid. Cover with slow cooker lid and cook on high for two hours.
- After chicken is cooked, drain off most of the liquid and pour it into a medium saucepan. Bring sauce to a simmer and cook until it thickens, about 5-10 minutes. Meanwhile, keep chicken warm in slow cooker on the warm setting.
- Serve cooked chicken, sliced, with thickened sauce on top and garnished with fresh scallions.