Nicolaas (Nico) Cortlever (14 June 1915, in Amsterdam – 5 April 1995) was a Dutch chess master.
He tied for 7-8th at Rotterdam 1936 (10th NED-ch, Salo Landau won); took 2nd at Amsterdam 1938 (11th NED-ch, Max Euwe won); won at the 2nd Hoogovens Beverwijk 1939 (Quadrangular); tied for 4-6th at Amsterdam I and 3rd-4th at Amsterdam II in 1939.
During World War II, he tied for 2nd-3rd at Beverwijk 1940 (Quadrangular, Euwe won); shared 1st with Landau and Lodewijk Prins at Leeuwarden 1940; took 2nd, behind Arthur Wijnans at Beverwijk 1941 (Quadrangular); tied for 14-15th at Munich 1941 (the 2nd Europaturnier, Gösta Stoltz won).
[3][4] Cortlever represented The Netherlands in Chess Olympiads: He won individual silver medal at Dubrovnik 1950.
[5] Cortlever was awarded the International Master (IM) title in 1950.