In a large bowl, combine tomatoes, onions, garlic, Worcestershire sauce, balsamic vinegar, cilantro, salt, pepper, and thyme.
Add chicken, making sure to completely coat it in marinade. Cover and refrigerate for at least an hour.
Heat olive oil in a large dutch oven. Add sugar, stirring well so sugar melts. Turn heat up to high and stir until sugar starts to brown. Be careful not to burn it.
Transfer chicken from marinade into dutch oven and brown on all sides. You may need to do this in batches. Once browned, transfer to a plate.
Add remaining marinade from bowl into dutch oven. Add water and ketchup and stir well. Transfer chicken back into pot and bring to a boil. Reduce heat, cover, and cook for 40 minutes. After 40 minutes, remove lid and stir, turning chicken if needed, and continue to cook for an additional 20 minutes until sauce has thickened and chicken is falling apart.