Iraklia is a small island with little tourist development, therefore it is not famous for its vivid nightlife. Instead of bars and clubs, visitors will find a nice selection of taverns and a couple of cafeterias in Agios Georgios, the port of Iraklia, which usually close before midnight.
If you are interested in nightlife, there are plenty of options on the neighboring island of Naxos, only an hour by ferry from Iraklia. There, you will find bars that stay open till the early hours and nice beach bars that frequently organize parties. Iraklia is a small island that offers relaxation and good food.