 Nicolls retired from the Royal Marines, and was given the substantive rank of lieutenant colonel, on 15 May 1835. On 3 November 1840, he received the brevet British Army rank of colonel, postdated to 10 January 1837. He was awarded a good-service pension of £ 150 per annum on 30 June 1842. On 9 November 1846 he was promoted to the brevet Army rank of major general, in June 1854 he was advanced to lieutenant general, and just a year later in June 1855 he was promoted to full general. In July 1855 he was made Knight Commander of the Order of the Bath (KCB).
