Throughout her career, Niles has worked with many artists including ABC, Eric Clapton, Kiri Te Kanawa, The Rolling Stones, Annie Lennox, Tears For Fears, Duran Duran, Kylie Minogue, David Bowie, The Police, Take That, Grace Jones, Tina Turner, Paul McCartney, George Harrison, Steve Winwood, Morrissey–Mullen, Snowy White, Tom Jones, Marillion, Fish, Pet Shop Boys, Buddy Guy, B*Witched, Victoria Beckham, Nick Carter, Living in a Box, Cliff Richard, Mike + The Mechanics, Zucchero, Status Quo, Robbie Williams, Bill Sharpe, Gary Numan, Wham!, Andrew Ridgeley, Dusty Springfield, The The, Jimmy Nail, Cher, Cabaret Voltaire, Seal, Liza Minnelli, John Denver and The Escape Club.
In 1991, the band released their debut album, Blue Movies, again featuring Niles as lead vocalist.
Niles has also voiced and sung on various television commercials for products including Barbie, Levi's, Cadillac, Diet Pepsi, Delta Air Lines, Aquafresh, KFC and DHL.
Niles also performed at Live Aid at Wembley in 1985, where she provided backing vocals for David Bowie (who introduced her as "Theresa" in the prelude to "Heroes").
On 16 & 17 June 1989 she performed vocals at Cliff Richard's gigs: From a Distance: The Event recorded at Wembley Stadium.