The Croatian joined the Toffees in January 2011 and has since scored 12 goals in 18 Premier League appearances following his brace in yesterday's 3-1 win over Southampton suggesting to Coleman that he has quickly adapted to England's top flight.
"He has been massive since he joined in January," said teammate Coleman.
"He scored a lot of goals in Scotland and people may have wondered whether he could do it here but he's come down and made it just as easy.
"He is a fantastic striker and if you give him half a chance he'll score a goal. It is great he has been scoring regularly.
"As players it's great that if you put the ball in the area there is a chance you'll end up with a goal from Niki - it gives the whole team confidence."