"What I saw was shocking, but it has made my job easier. It will also help me in my further investigation," he told reporters.
Nanavati saw the footage at the BCCI headquarters here with IPL Commissioner Lalit Modi, BCCI secretary Niranjan Shah and Joint-Secretary M P Pandove.
He will submit his inquiry report on the matter to BCCI president Sharad Pawar on May 12.
Nanavati has already summoned Harbhajan and Sreesanth to Ahmedabad this weekend, though Sreesanth is yet to confirm when he will reach the city.
The Board of Control for Cricket in India has already imposed an 11-match Indian Premier League (IPL) ban on Harbhajan Singh after he admitted to slapping pacer Sreesanth following their match on April 25.
Sreesanth was reprimanded for provoking the off-spinner and warned about his behaviour.