Because it is a popular dish from the Chettinad region of Tamil Nadu. It makes use of various spices commonly used in their recipes such as coriander, cumin, red chilies, coconut, cloves, black pepper, whole spices etc... which are all dry roasted and made into a thick masala paste and added into the curry to make good gravy for the chicken. It is commonly called Chettinad chicken kulambu.