The Kiwi is convinced by the ambitions of owner Evangelos Marinakis.
He told the Daily Mail: "Long-term, the sky is the limit.
"The owners are growing the club and trying to do it correctly across the board to build for sustained success.
"It's not a case of doing well in the Premier League for one season. It's about doing well consistently and being ambitious to challenge for European football and for titles in years to come. It might take a while, who knows?
"I'd like to think Forest could win another top-flight title. As long as the club keep progressing on and off the pitch, they definitely could. Our owners want to build so we push for Europe and titles, and they believe we can.
"But the things that have been done, especially during my time here, have given the club a great chance to progress. We are in our third season in the Premier League now and that's when you start to feel you're an established club. Now it's about closing the gap."
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