Nixon was born in Whitmore Square, Adelaide, South Australia, on 17 March 1871. She was the eldest of eight children born to Thomas Mayfield (1842–1920) and Elizabeth Webber (1852–1889). Her father was born in England, while her mother was born in Wales. After her mother passed away, she helped her father raise her younger siblings. Her youngest brother, Alfred Irving, was killed during World War I in Somme, France in 1916.
On 16 December 1890, at the age of 19, she married Albert Willian Nixon (1871–1945), a bookmaker from North Adelaide. The couple had 7 children.
Nixon entered hospital for the first time at the age of 89. She was blind and deaf and a centenarian. She attributed her longevity to eating plain food, working hard, and having a close family.
Nixon passed away in North Adelaide, South Australia on 10 May 1982, at the age of 111. She was survived by 32 grandchildren, 106 great-grandchildren and 108 great-great-grandchildren.