Karrueche, who was Chris' girlfriend at the time, actually had her arm around Nia in a photo they took -- with Christina Milian too -- during a Las Vegas party back in May 2013. Chris was nearby ... mean-mugging with his homies.
Check out the photo below:
Nia allegedly got pregnant with Chris' baby later that summer. We're guessing the ladies won't be having a reunion anytime soon.
According to TMZ, Nia was very popular on the video vixen scene ... appearing in several music videos, including a half-naked role in Phill Wade's "Dreams of You" video.
Photo: Getty Images