The Reason Is Call King of kings

The Bible calls Nebuchadnezzar king of kings because he ruled over all the kingdoms at the time, he was the golden head of the statue, and inferior kingdoms would take him down because of his pridefulness

Jesus is called King of kings because he rules every kingdom and received his authority from heaven. This is why in the Gospel he said all power in heaven and earth has been given to me and why Isaiah said the increase of his rulership will have no end