Nicholas Greaves, D.D. (1605?–1673) was an English churchman who was Dean of Dromore cathedral, County Down.
He was the second son of John Greaves, rector of Colemore, near Alresford, Hampshire. His brothers were John Greaves, Sir Edward Greaves and Thomas Greaves.
He studied as a commoner at St. Mary Hall, Oxford. He was elected fellow of All Souls' College in 1627, and junior Proctor of the University in 1640 (a position also held by his brother John's nemesis, Nathaniel Brent in 1607) In 1642 he became the rector of Tullylish, Co. Down. The parish, in the Church of Ireland diocese of Dromore, is part of the original endowment of the Dromore deanery. The church had been partially destroyed during the Irish rebellion the previous year. Greaves held the living until 1673.
On 1 November 1642 he took his Bachelor of Divinity degree, and D.D. on 6 July 1643. He was presented as Dean of Dromore Cathedral on 21 March 1643, but not necessarily installed. The Bishop of Dromore was Theophilus Buckworth, the brother-in-law of archbishop James Ussher. Ussher was a friend and correspondent of Greaves' oldest brother, John Greaves. Buckworth had restored the old Dromore cathedral between 1613–1622 and begun to build a new bishop's palace; but they had been burned down along with the rest of the town on 15 November 1641 during the rebellion of that year. Buckworth was forced to flee to England, and returned to his place of birth at White Hall manor near Wisbech, Cambridgeshire. This is probably connected with Greaves' time at St. John's College, Cambridge.