New Zealand, who will host the British & Irish Lions in 2017, face clashes with USA, England, Scotland and Wales next month.
And less than a year out from the 2015 Rugby World Cup, Mains - who coached All Blacks legend Lomu during his tenure - expects the 24-year-old flyer to show his worth once more.
"While he possesses pace and power, he is much stronger on defence than Lomu ever was and goes looking for work.
"However, one of the great rugby tragedies is that when Jonah should have been hitting his peak, he was struck down with a kidney disease. Who knows how good he may have been?"