Nick O'Hern was tied with Stuart Appleby and Peter O'Malley another stroke back, while Rod Pampling and American Eric Egloff were among seven players in a share of seventh place at 5-under.
U.S. Open champion Geoff Ogilvy opened with a 68 and was at 4-under with two-time champion Peter Lonard, while defending titlist Robert Allenby recovered from a bad start for a 70.
Nitties, runner-up to Lonard here in 2004, had nine birdies, eight pars and a bogey in his opening round.
Adam Scott, ranked fourth in the world, had a 72 and believes he can make a charge in the second round if he adjusts to the greens in subtropical conditions at Coolum.
'There is a bit of a knack to reading them, you've got to get the grain right,' Scott said. 'I certainly was fooled a little bit today. I over read a lot of putts, so I have to get my eye in quick tomorrow and get up that leaderboard.'
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