Tamil nationalism got crushed permanently, when LTTE was disbanded and destroyed.
Tamil nationalism in Tamil Nadu goes well before the formation of LTTE or even the birth of its founder Commander Prabakaran. He was born in 1952 and first open demand for independent Tamil Nadu was made in 1938.
Tamil nationalism in "Tamil Eelam" (northeastern Sri Lanka) surpassed that in Tamil Nadu because of the able leadership of LTTE.