After the war, Nash lived at Wormingford in Essex. He joined the staff of the Royal College of Art in 1945 and continued to teach there and later at the Flatford Mill field studies centre. When in Essex, Nash taught at Colchester Art School and in 1946, along with Henry Collins, Cedric Morris, Lett Haines and Roderic Barrett, became one of the founders of Colchester Art Society and later the Society's president. Nash bequeathed his personal library and several of his paintings and engravings to The Minories, Colchester, who later sold most of the material to the Tate. Nash became an Associate of the Royal Academy in 1940 and a full member in 1951. He became a Commander of the Order of the British Empire (CBE) in 1964. His retrospective exhibition at the Royal Academy in 1967 was the first for a living painter.