The Chief Justice of Nigeria or CJN is the head of the judicial arm of the government of Nigeria, and presides over the country's Supreme Court and the National Judicial Council The current Chief Justice is Ibrahim Tanko Muhammad who was appointed 22 March 2019. CJN - Frequently Asked Questions. All the full form of CJN with definition and full meaning. What does CJN Full From stand for, Meaning, What is Full Form is? Check CJN meaning is Chief Justice of Nigeria where all Abbreviation, Acronym of CJN is. Walter Samuel Nkanu Onnoghen, GCON (born 22 December 1950) is the former Chief Justice of Nigeria.