The pair were together during an interview on CNN and Nicklaus took the opportunity to question McIlroy's decision to play in this week's St Jude Classic in Memphis.
Nicklaus asked: "Did you play the week before The Open last year?"
McIlroy replied: "No."
The 18-time major winner then went on to offer advice to McIlroy about tournament preparation before admitting that he wants the Northern Irishman to "get smart" soon.
Nicklaus said: "In 1962 when I turned pro I played the week before the Masters. People wanted me to play and I didn't do well. I skipped that tournament the next year and I won the Masters.
"I went back to that tournament the next year and didn't win the Masters. Then I skipped it the next year and won the Masters. Skipped the tournament the year after and won the Masters again. I am a huge fan of Rory's but I want him to get smart young."
McIlroy has missed the cut in his last three tournaments.