He was apprenticed to Joseph Wyeth, merchant in London, and, after serving his time, became a partner with his father.
From Wyeth's widow Nickolls received a number of letters at one time in John Milton's possession; they had since belonged to Milton's secretary, Thomas Ellwood, and had been used by Wyeth in the preparation for publication of Ellwood's Journal, which was issued in 1713.
[2] William Oldys visited Nickolls at Queenhithe on 22 December 1737, to see this collection of original letters.
[3] Oldys says in his diary that Nickolls allowed Thomas Birch to use some of them in his life of Oliver Cromwell in the General Dictionary, Historical and Critical, 1731–41.
On 18 January 1746, Nickolls' father presented the original manuscripts from his collection to the Society of Antiquaries.