Kean returned to the club after a successful loan to PSG last season, in which the Italian striker scored 13 goals in 26 league appearances.
There has been speculation about the future of the 21-year-old, who still has three years on his contract at the club.
READ MORE: Moise Kean surprises as Rafa Benitez and Everton warn of ’emotional’ striker
While a move this summer remains a possibility, Nevin believes Kean could still have a lot to offer Goodison Park.
“I watched Moise Kean before he came to Everton, and thought it would be one of the best deals in club history,” Nevin told TribalFootball.com (on behalf of British Gambler) .
“He looked amazing before he got there, but it just hasn’t worked out for him so far.
“If Rafa can get the best of him alongside Dominic Calvert-Lewin, then they will be a force of attack. “
However, it’s not just Kean that Nevin is excited to see in action.
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The 57-year-old has claimed Gray could be the real difference maker for the Toffees, following his summer transfer from Bayer Leverkusen.
“Demarai Gray may be the big one, he’s an incredible talent and there were times in Leicester where he looked like the next Riyad Mahrez,” Nevin said.
“If Rafa can get the best of him and Moise Kean then Everton will have a very good season. ”