Sierra Leonean diplomat, physician, medical researcher, and writer whose short stories and poems are among the best to have come out of West Africa.

Nicol was educated in medicine and natural sciences in Sierra Leone, Nigeria, and England, and he subsequently served in various medical posts in those countries. He became known for his research into the structure of insulin, and he lectured and wrote widely on medical topics. He was principal of Fourah Bay College, Freetown (1960–68), vice chancellor of the University of Sierra Leone (1966–68), and his country's ambassador to the United Nations (1969–71). Nicol was president of the UN Security Council in 1970, and from 1972 to 1982 he served as executive director of the United Nations Institute for Training and Research (UNITAR). He was president of the World Federation of UN Associations from 1983 to 1987.

Nicol's short stories were published in Two African Tales (1965) and The Truly Married Woman, and Other Stories (1965), under the name Abioseh Nicol. They centre upon life in the government service and upon the interaction of Africans with colonial administrators in preindependent Sierra Leone. His short stories and poems appeared in anthologies and journals. He also wrote Africa, A Subjective View (1964) and edited several other nonfiction works.

Nicol from 1957 was a fellow of his college at the University of Cambridge, the first African to be so named at either Cambridge or Oxford.