The 63-year-old Nazario has been acting as presiding justice since late last year after Francis Garchitorena was forced to file an early retirement.
Nazario, the first woman to head the Sandiganbayan, also chairs the special division which has been hearing the plunder case against ousted President Joseph Estrada.
Presidential Spokesman Ignacio Bunye denied speculations that Nazario’s appointment is a "reward" for her performance in the Estrada trial.
"Not at all," he said. "(Nazario) was recommended by other justices at the Sandiganbayan and at the Supreme Court... plus the fact that she was the most senior among them."
For his part, Estrada welcomed Nazario’s choice as the new Sandiganbayan presiding justice, after The STAR informed him about it.
"She has been the acting presiding justice of Sandiganbayan anyway," he said. "She deserves it."
Nazario was named first woman justice of the Sandiganbayan on May 10, 1993, and served as judge of the Laguna Regional Trial Court from 1987 to 1993.
She joined the anti-graft court in 1981 as First Division Clerk of Court, when Manuel Pamaran, one of Estrada’s lawyers in the plunder case, was presiding justice and chairman of the First Division.
Nazario started her career in the judiciary in May 1973, when she transferred from the Department of Justice to the Supreme Court’s reports and statistics division.
From 1974 to 1979, she served as senior judicial assistant to then Chief Justice Fred Ruiz Castro.
In 1979, she was detailed to the office of then Deputy Court Administrator Leo Medialdea.
Nazario has been in government service in various capacities since 1962, after she graduated from the College of Law of the University of the Philippines.
She first worked as social secretary of then Justice Secretary Juan Liwag and later as clerk in the Manila city fiscal’s office.
Nazario was admitted to the New York state Bar in 1988.
She was examiner in criminal law during the 2000 Bar exams.