According to Entertainment Weekly, Nicole "will resurface in October when a prison transfer goes awry and her character, Heather Chandler, ends up being stowed away at Castle (a.k.a. the underground CIA base)."
And her character is making a cameo in the nick of time--just as Chuck and Sarah are hitting a rough patch in their relationship. As you may recall Heather is Sarah's high school nemesis and they had a bloody fight two years ago.
EW also reports that wrestler “Stone Cold” Steve Austin will be returning to Chuck for the same episode, in his role as Hugo Panzer.
Set your TiVo's because it’s sure to be a kick ass cameo.