Niecy was born in L.A. but spent most of her childhood in St. Louis, Missouri. As a child, Niecy's desire to be a performer was inspired by Lola Falana. Niecy majored in theatre at Cal State Dominguez Hills, and graduated with a BA. She is married with three children. Niecy is the host of Clean House on the Style Network and also stars as Raineesha Williams on Reno 911! on comedy Central. Niecy also sings in her husband Don Nash's gospel group. In 1995, the group won first prize at the McDonald's Gospelfest. Along with Ronda Noel, Niecy started her own production company called Noel Nash Entertainment. Niecy is the spokesperson for M.A.V.I.S. or Mothers Against Violence in Schools. M.A.V.I.S. was founded by Niecy's mother in 1993 after Niecy's younger brother was shot and killed at his high school.
Nash's credits include the films Boys on the Side, Guess Who, Hair show, Cookie's Fortune, The Bachelor, and Malibu's Most Wanted. Her tv credits include Reno 911!, Clean House, The Bernie Mac Show, Presidio Med, That's Life, Popular, City of Angels, Monk, CSI, Girlfriends, NYPD Blue, That's So Raven, One on One, Judging Amy, and Reba.