A nickname for a leader could be boss, chief or head honcho.
The Leader; nickname for Hitler
Iowa's nickname is "The Hawkeye State". It is a tribute to Indian leader chief Black Hawk, leader of the native American Sauk tribe.
Moses in Hebrew is Moshe (משה) but he didn't have a nickname.
That was Ivan.
During the Civil War, the leader of the Underground Railroad was Harriet Tubman. A common nickname for Harriet Tubman was Moses.
Jawaharlal Nehru
Gorby was a nickname given to Mikhail Gorbachev when he was leader of the USSR.
What are sandwiches made off
I'm not sure it was a nickname but he called himself "Il Duce". Means leader or Duke.
because they whanted it to be that after their leader Frank Tucker
II Duce
The leader goes by the nickname "Ib" pronounced "eeb"