In 1923 Nash became a member of the Modern English Water-colour Society. In 1923 he worked in Dorset and in 1924 in Bath and Bristol. From 1924 to 1929 he taught at The Ruskin School of Drawing and Fine Art (Oxford). In 1927, he wrote and illustrated a book on "Poisonous Plants". From 1934 to 1940 he taught at the Royal College of Art in London, working on wood engravings and lithographs. In 1939 he visited the Gower Peninsula, near Swansea – the first of many visits to Gower and other parts of Wales.