Nicholls appeared in the BBC film Persuasion (1995), an adaptation of Jane Austen's novel. She has made guest appearances on several television mystery series, including Kavanagh QC, Prime Suspect, Midsomer Murders, Lewis, The Ruth Rendell Mysteries ("May and June", 1997), Foyle's War, Second Sight starring Clive Owen, and the 2012 Christmas episode of Downton Abbey, a role she reprised for the 2014 season. She has also appeared in several works directed by her husband, Charles Sturridge, including his 1995 television adaptation of Gulliver's Travels, where she portrayed the Liliputian Empress, the 1997 film Fairy Tale: A True Story and Shackleton in 2002.
