In a large skillet over medium heat, add the oil. To the oil, add the onion and garlic and cook for 5 minutes then add the chicken. Cook chicken for 10 minutes, until brown. Pour the mixture into a large crock cooker and then add the remaining ingredients and cover with the lid. Cook on HIGH for 2 to 4 hours, or until all the veggies and chicken are cooked through. Serve hot.