She made a second appearance in the Season Six episode, "The Biggest Douche in the Universe". Chef takes Cartman and his mother to his parents' manor house in Scotland. She performs a shaman-esque ritual to exorcise Kenny's soul from Cartman's body. Although she is successful in exorcising Kenny's soul she is unable to re-seal it because Chef hadn't brought a victim child to sacrifice. Instead, Kenny finds his way into a pot roast Nelle was preparing, much to her dismay.
Her most recent appearance to date is in "Red Sleigh Down", where she is seen along with Chef in a crowd during the town's Christmas celebration. She is not seen at Chef's funeral in "The Return of Chef".
She appears to be very old, with wrinkles and grey hair. She has a full head of curly grey hair and wears a yellow dress and a pearl necklace. Her eyes seem to be perpetually closed. She also appears to carry a small blue handbag around. In "The Biggest Douche in the Universe", she appears in full voodoo regalia, with a long white robe, an intricate mask and headdress, fake wings and one scepter in each hand.
She appears to be friendly, being very accommodating to Liane Cartman and Eric Cartman when they visit her house in "The Biggest Douche in the Universe". Nellie appears to be a little senile and over-concerned with household duties, worrying about Kenny's spirit getting all over the curtains and her pot roast, and occasionally muttering things to herself.
She appears to have a good relationship with her son, Chef. He lives in the USA, and she appears to miss him a lot. When he appeared at their doorstep in Scotland she was overjoyed to see him again.
Nellie and Thomas both love each other very much. They argue constantly over their frequent encounters with the Loch Ness monster.
- "The Succubus" - Comes down to South Park for Chef's wedding.
- "The Biggest Douche in the Universe" - Chef brings Cartman and his mom to see his parents to help them exorcise Kenny McCormick's spirit from Cartman's body.
- "Red Sleigh Down" - Seen in the crowd with Chef during the Christmas celebrations.