Golden Boot winner Tuivasa-Sheck will line up for the Warriors in the NRL again next year, bringing to a close his two-year foray into rugby union.
He has spent time in the centres in the 15-man code and appears destined for the same with the Auckland-based league side.
Ahead of Friday night's clash with his former club Canberra at GIO Stadium, Nicoll-Klokstad got a vote of confidence from coach Webster.
"He's improving the little things to have a big impact ... he does whatever the team needs and puts the team first and that's what's impressed me," Webster said of the 27-year-old.
"He gives middle forwards headaches all day, he keeps going at them, he's tough and we love him."
Asked whether having to choose between Nicoll-Klokstad and Tuivasa-Sheck to play fullback was a dilemma, Webster stated it wasn't.
"Charnze will be in the team next year, at fullback, he will be our No.1," Webster said.
"Roger's a world class player that will have a huge impact on this team but you want to have the best 17 players available and they're both going to be in there and in positions they can both comfortably play at a high level.
"Charnze isn't going anywhere."
The Raiders are currently sixth, two points and one spot ahead of the Warriors with both teams coming off a win.
Webster lauded their 22-point victory over the Dolphins as their best defensive performance of the season.
"I thought we were the most dominant we've been with our defence," he said.
"We've had heaps of good moments on our tryline this season but I thought it was the best we'd been stopping them coming off their line, getting field position.
"It was really pleasing ... we thought it was one of our best performances."
