Nisar, 62, replaced Justice Anwar Zaheer Jamali who retired yesterday after superannuation.
The oath-taking ceremony held in the President House called "Awan-e-Sadr" was attended by Prime Minister Nawaz Sharif, Chairman of the Senate, Speaker of the National Assembly, federal ministers, services chiefs, parliamentarians, diplomats and judges.
Pakistan's President Mamnoon Hussain administered oath to the new Chief Justice of Supreme Court. Hussain appointed Nisar as the country's top judge on December 7 ahead of retirement of Jamali who served as chief justice for 15 months since his appointment in September 2015.
He was serving as judge of the Lahore High Court.
He was senior lawyer before elevation the post of judge of the high court and remained member of the Supreme Court Bar Association and Lahore High Court Bar Association (LHCBA).