Reigning national champion and National Games gold-medallist Nanao was in fine form as he devoured Ladon Rogen of the Philippines in what turned out to be a one-sided contest.
The 22-year-old, with his combination punches and excellent ring movement, made it if very difficult for the Philippines boxer to settle down and find his rhythm.
The Indian went on to make a place in the semi-finals with a 12-8 win. In the round of four, he will take on Ri Chung Hyok of DPR Korea.
He emerged victorious with a score of 17-6, relying mostly on his straight punches and counter-attacks.