The singer, 41, fronted the band alongside Carmit Bachar, Ashley Roberts, Jessica Sutta, Melody Thornton and Kimberly Wyatt from 2003 to 2009, when the "Don't Cha" hitmakers split following alleged conflicts over Nicole's dominance in the group.
According to Britain's The Sun newspaper, the group are plotting a comeback, and have once again tapped the star - who has since enjoyed a successful solo career - to front the band.
"Nicole has long turned down offers for a reunion but with the ten-year anniversary of their hiatus passing, she finally said she was ready," the insider claimed. "Nicole was made a multi-million (dollar) offer to re-join the group and was given a huge advance which made it impossible for her to turn down."
The source claimed all six members are on board for the comeback - including Carmit, who quit in 2008 shortly before the release of their second album "Doll Domination" - and a worldwide tour has been pencilled in for 2020.
Revealing the group will be "playing their greatest hits", the insider added, "There has been talk of the possibility of them recording new music.
"It's in the early stages but now they're going to be back together, a couple of them, including Nicole, have said they'd be open to working on some new sounds together."