He said he was "loving the attitude and the energy of the team this season".
Nahu admitted there was "plenty to work on" for the decider against Mangakino next Saturday.
The Chiefs lost 26-18 to Mangakino in the playoffs, but they now have a second chance.
"We will have to complete our sets better. We gave away too many unnecessary penalties today."
Paul's father Nick wore a large grin as he watched his coaching son and playing grandsons Corey and Blake take the win.
Nick Nahu has been a part of the club for 51 years and has only missed one game this season when he had a nephew's wedding in Nelson to attend.
"I thought it would be a close game today. Pacific are always hard to beat," he said on Saturday.
"They did a lot of tackling, which worked well for them."
The Pacific Sharks, who travelled from Tokoroa, were gracious in defeat.
Coach George Turia said the loss came down to the team's bad start to the match.
"We gave away three quick tries. Our defence lost us points in the first 15 minutes."
He said it was a "disappointing" end to the season, but there were standout performances.
"Denzil Manu had an awesome game," Turia said.
The No 5 scored two tries, but that was a feat Ngongotahā players Tai Kapua and Max Redstone also matched.
Turia said it was "the first time in about seven years" the Sharks had not made the final, but he wished Ngongotahā "all the best".