In early July 1995, when the Bosnian Serb Army staged its attack on Srebrenica, Nikolic was deputy commander for security and intelligence of the Bratunac Brigade, which was involved in the events.
Početkom jula 1995. godine, u trenutku kada su se bosanski Srbi pripremali da napadnu Srebrenicu, Nikolić je bio pomoćnik komandanta za bezbednost i obaveštajni rad Bratunačke brigade koja je učestvovala u događajima koji su usledili.