Her stage debut was at the National Theatre in Belgrade as Third Lady in Mozart's The Magic Flute; she then sang Tisbe in Rossini’s La Cenerentola.
In 2001, Nikolic won a two-year scholarship for the Teatro alla Scala Academy for the Specialisation of Opera Singers which allowed her to complete her studies under Leyla Gencer, Luciana Serra, Giovanna Canetti, Luigi Alva and Teresa Berganza, and further develop her operatic ability under the batons of conductors including Gary Bertini and Riccardo Muti.
In 2006, Nikolic sang La Baronne in Massenet's Chérubin and Fenena in Verdi's Nabucco for the Teatro Lirico in Cagliari, Sardinia.
Her collaboration with Opera Australia began in 2006, singing Ježibaba in Dvořák's Rusalka and continued with performances as the Princess in Puccini's Suor Angelica, Azucena in Verdi's Il trovatore and Venus in Richard Wagner's Tannhäuser.
[3] In March 2010, Nikolic created the role of Mrs Dalton in the world premiere of Brett Dean's opera Bliss and she will travel in 2011 with that production to the Edinburgh Festival.