Born in the late '40s in Scotland, Nicols quit school in her mid-teens to work as a dancer at the Windmill Theatre, and a year later, secured her first singing gig in a local strip club. In addition to some traveling as a dancer, which included several months in Paris, Nicols became a dedicated jazz fan and began singing around Britain, sometimes collaborating with bebop pianist Dennis Rose. In 1968, she joined an early improvisational group, with John Stevens, Johnny Dyani, and Trevor Watts, the Spontaneous Music Ensemble, and the group performed that year at Berlin's avant-garde festival, First Total Music Meeting. Around this time, Nicols also began collaborating with the Scottish percussionist Ken Hyder (who had recently moved to London), and formed a vocal group called Voice (which had one self-titled release) with vocalists Brian Ely, Phil Minton, and Julie Tippett -- the latter two were also in another band with Nicols at that time; Keith Tippett's enormous ensemble, Centipede. Nicols and Julie Tippett also led a release for the FMP label in the late '70s, called Sweet and S'Ours.

By the late '70s, Nicols became an active feminist and co-founded the group OVA, as well as the Feminist Improvising Group, with Lindsay Cooper. She also organized Contradictions, a women's workshop performance group that began in 1980 and dealt with improvisation and other modes of performance in a variety of mediums including music and dance. Over the years, Nicols has collaborated with other women's groups such as the Changing Women Theatre Group, and even wrote music for a prime-time television series Women in Sport. Nicols has also collaborated regularly over the years with pianist Irene Schweizer and formidable bassist Joelle Leandre, including tours and recordings (Les Diaboliques on Intakt) as a trio. In addition to this is her ongoing collaboration with Ken Hyder. The duo incorporates elements of the traditional tunes of their shared Scottish background into jazz improvisations in their most recent project, Hoots and Roots Duo (their album In the Stone was released in the '90s on Impetus Records). Other continuing projects for Nicols include a duo with pianist Pete Nu (they have 1980s albums on Leo Records including Don't Assume), a singing duo with her daughter Aura Marina, and Light and Shade, a project with lighting designer Sue Neal.

Maggie Nicols has performed internationally for several decades, including solo performances at the Moers Music Festival and a number of other creative and improvised music festivals. She has worked with a great many improvisers from all over the world including drummer Gunter "Baby" Sommer, British soprano saxophonist Lol Coxhill, Anna Marie Roelofs (who leads the group the Waste Watchers), the Australian Relative Band (with Jim Denley), the Loverly Band, Trevor Watts' Moire Music, and Al Dente.