The former world No.1 needs four more majors to equal Nicklaus' mark, but the 40-year-old has not won one of golf's big four events since the 2008 US Open and has not played competitively since August 2015 after multiple back surgeries.
Woods was asked in an interview to be aired Thursday on "Charlie Rose: This Week on PBS" whether he still thinks he will get to 18 majors.
"To be honest with you, no," he replied.
When Rose asked if he had accepted that, Woods laughed and said
: "I've accepted I'm going to get more."
Woods's world began to unravel when his serial infidelities came to light in 2009, leading to divorce from wife Elin.
But in answering a question about the burden of being Tiger Woods, he said: "The only regret I have in life is not spending another year at Stanford."
When Rose pushed him, given the public humiliation and fall-out from the scandal, he replied: "All the things I've been through are tough, yes. They've been tough, but they've been great for me. But I wish I would've gone one more year at Stanford."
Later Woods added: "I made a bunch of mistakes. But in the end, Elin is my ex-wife. She's one of my best friends. We've had two beautiful kids."
Woods, who was one of captain Davis Love's non-playing assistants at the Ryder Cup, was due to make his playing return at the Safeway Open in Napa earlier this month, but withdrew saying his game was "vulnerable and not where it needs to be."
He also pulled out of the Turkish Airlines Open but said he hopes to play at his foundation's Hero World Challenge event on December 2.
Woods has not won a PGA Tour event since the World Golf Championships-Bridgestone Invitational in August 2013, but is striving to add to his total of 79 titles and close in on Sam Snead's all-time record of 82.