Was commissioned Assistant Surgeon to the 1st Foot Guards on Dec 25th, 1796. This, says Colonel Johnston in a note, is “the earliest date of a Regimental Assistant Surgeon's commission, though not the first to be gazetted”. The first to be gazetted was Robert Lawson, Assistant Surgeon to the 4th Dragoons, Feb 2nd, 1797. Nixon was gazetted Surgeon to the same Regiment on March 20th, 1799, being styled Battalion Surgeon after 1804. On June 9th, 1814, he was promoted to Surgeon Major, and on Nov 10th, 1824, was made Inspector of Hospitals, and later Inspector-General of Hospitals. He served in the Peninsular Campaign in 1812-1814, and held the local rank of Deputy Inspector of Hospitals in Spain and Portugal only, from Sept 10th, 1812. He retired on half pay on Nov 11th, 1824, and resided or practised at Papplewick, Notts, where he died on April 13th, 1853.