The former Manchester United coach was named Foxes manager on Friday afternoon.
The Dutchman revealed he spoke with Maresca, who led Leicester to promotion from the Championship last season before leaving for Chelsea.
Van Nistelrooy said: “I have to say, when the interest came, the first one I called was Enzo.
"He was so positive about it. He absolutely loved his time. When you hear these things, it’s a club you want to be a part of. Obviously, with the interest coming, I phoned him and I asked him more detailed questions about the Club, the structures, the people that work there, the squad, the stadium, the fans, the town, the surroundings… it was a fantastic conversation. It’s always a pleasure to talk to him.”
Van Nistelrooy will kickoff his Leicester career with two homes games next week against West Ham and Brighton.
He also told Leicester's website: “I’m looking forward to that.
“The preparation will be short for the West Ham game, but we’ll get to know each other and get our focus on the West Ham game at home. It’s a new start and something to look forward to. When the connection is made at King Power Stadium, then we’ll know what can happen there.
"You start to play with 11 and then you go to 12, you get the extra bit there, and it’s something which is vital in this period for the Football Club.”
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