In April 1915 (during WWI) he was delegated to England and America by the Serbian Church, where he held numerous lectures, fighting for the unison of the Serbs and South Slavic peoples. At the beginning of 1919 he returned to Serbia, and in 1920 was posted to the Ohrid archbishopric in Macedonia, where in 1935, in Bitola he reconstructed the cemetery of the killed German soldiers.
During the Second World War in 1941 Bp. Nikolai was arrested by the Nazis in the [[Monastery]] of Žiča (which was soon afterwards robbed and ruined), after which he was confined in the Monastery of Ljubostinja (where, on the occasion of mass deaths by firing squad, he reacted saying: "Is this the German culture, to shoot hundred innocent Serbs, for one dead German soldier! The Turks have always proved to be more just..."). Later, this "new [[John Chrysostom|Chrysostom]]" was transferred to the Monastery of Vojlovica (near Pančevo) in which he was confined together with the Serbian patriarch, [[
Gavrilo (Dozic) of Serbia|Gavrilo (Dožić)]] until the end of 1944.
On [[December 14]], 1944 he was sent to Dachau, together with Serbian [[Patriarch]] Gavrilo, where some sources, especially the standard Church references, record that he suffered both imprisonment and torture.[http://www.serfes.org/lives/holyhierarchsaintnicholai.htm]