She made multiple appearances on ABC's The Catch in a recurring role playing the matriarch of a London gangland family and also guest-starred on episodes of Amazon Prime Video's The Boys, ITV's Doc Martin, The CW's Supernatural (where she played a variation of the witch from Hansel and Gretel), CBS's reboot of The Odd Couple, ABC's Once Upon a Time and TVLand's Hot in Cleveland.

On stage, Nicol co-starred as "Rosie" in the original West End production of the international hit musical Mamma Mia!

[16][17] She and Mueller first performed it in 2017 at her alma mater, London's Guildhall School of Music and Drama, followed by a show in Hong Kong at that city's historic Fringe Club theatre.

[19] The show's North American tour in the summer of 2022 was postponed to a due to the death of her husband, reported as a "deep personal bereavement.

[21] Unlike her Downton Abbey character, Mrs Patmore, Nicol is a vegan and, by her own admission, is a "terrible" cook.