In addition to fiction, essays, theatre scripts and children's books, he wrote non-fiction works on travel, politics, religion, cats, parapsychology, and autobiography.

The trilogy chronicled the difficulties and delights of maintaining a Tudor thatched cottage in Glatton, Huntingdonshire, the village he fictionalised as Allways.

[3] The three books were so popular that they led to humorous imitations, including Mon Repos (1934) by "Nicholas Bevel" (a parody by Muriel Hine) and Garden Rubbish (1936) by W. C. Sellar and R. J. Yeatman, a satire on garden writers, which included a Nichols-like figure named "Knatchbull Twee."

Nichols' final trilogy (1963–1968) chronicled his adapting to a more modest living arrangement, beginning in 1958, in a late 18th-century attached cottage ("Sudbrook") at Ham, near Richmond, Surrey.

He ghostwrote Dame Nellie Melba's 1925 "autobiography" Memories and Melodies (he was at the time her personal secretary, and his 1933 book Evensong was believed to be based on aspects of her life).

Nichols made one film appearance, in Glamour (1931), directed by Seymour Hicks and Harry Hughes, playing the small part of the Hon.

[8] Nichols died on 15 September 1983 and his ashes were scattered over St Nicholas' Churchyard, Glatton, Cambridgeshire, England.