Nikolov joins D.C. United from the Philadelphia Union where he had two stints as an Assistant Coach, the first from 2016-2017 and the second from 2019-2021. Between his spells with the Union, he spent a year as an Assistant Coach with the LA Galaxy. Nikolov also possess international coaching experience thanks to his time with the Macedonian National Team, as well as the German U19 National Team.

Prior to making the transition into the coaching side of the game, Nikolov had a 23-year playing career with 21 of those years spent with Eintracht Frankfurt in Germany where he made 452 appearances. He made the move stateside in 2013 where he joined the Philadelphia Union before a one-year stint with the Fort Lauderdale Strikers before retiring in 2014. Nikolov also made 5 appearances for the Macedonian national team between 1998-2001.