He secured himself a transfer abroad in 2009, aged just 19, to the Belgian Second Division side FC Brussels, where he would spend the next 3 seasons as a starter.

After his contract ran out, Nižić returned to Croatia and trained for a few months with HNK Hajduk Split, before signing with them in late 2012.

[3] He made his league debut for Hajduk on 16 February 2013, entering the game for the injured Matej Jonjić in a 2–0 away win against NK Slaven Belupo.

It was also revealed that he had a confrontation with a director of Hajduk, Saša Bjelanović, in the locker room, who eventually took away his role as a captain.

[9] Nižić made his debut for Croatia in a May 2017 friendly match against Mexico in Los Angeles and earned a total of 2 caps, scoring no goals.