Nickels is married to Kelly Cunningham, the mother of actress Emma Roberts. Nickels has a daughter with Cunningham, born in 2001.

Nickels started as a roadie/light man for the band Hotshot, which was an early incarnation of Danger Danger. In 1981, he joined metal band Virgin Steele. Nickels joined the band Sweet Pain in New York as a bassist, and released one album with them in 1985. Kelly and drummer Ronnie Taz, quit Sweet Pain, He was replaced by Victor Prestin. He moved on to the band Faster Pussycat, but was badly injured in a motorcycle accident (at an intersection on the Sunset Strip in California) in October 1986. Due to this injury his position in the band was replaced. His leg was broken in seven different places, and he had to walk with a cane for a long time afterwards.

By the late-1980s, he had joined L.A. Guns. He remained with the group throughout their most commercially successful period. In addition to playing bass throughout his tenure with the group, he also sang lead vocals on the L.A. Guns song “Nothing Better To Do,” from their 1994 album, Vicious Circle. However, he left the band shortly after this album was released. By the end of the 1990s, he was back in L.A. Guns, only to leave again in 2000.

Henri Perret (born January 5, 1962) known professionally as Kelly Nickels is a bassist who has played in various bands including Sweet Pain, Faster Pussycat and L.A. Guns.