
Veteran striker Jamie Vardy, 20-year-old Bilal El Khannouss and substitute Patson Daka scored as Leicester took their chances while a dominant West Ham were guilty of spurning several good opportunities, only getting a late consolation goal from Niclas Fuellkrug.
Van Nistelrooy was appointed on Friday to replace Steve Cooper after the Foxes made a poor start to the season and although he did not have much time with his new charges, his arrival injected some much-needed good fortune into the club.
The win moved Leicester, who last won six weeks ago, from a point above the relegation places to 15th, while West Ham are one place above them in the standings.