Nancy was known to be the first major child to actually torment Tom. During the Tom and Jerry short known as Baby Puss, she scolds Tom, forcing him to remain a baby which he gets heavily annoyed from (despite him enjoying the milk in the bottle that she feeds him). As soon as she was through she left the room for a couple of seconds, only for Tom to get tormented by Jerry, who had been watching the entire time. Tom is stopped just before he could catch Jerry, from the words of an angry Nancy. Tom's head was stuck in the dollhouse, and was yanked back on to his bed. Nancy warns him that if he moved from his spot one more time, she will feed him castor oil, in which filled Tom with fear. She tosses him his bottle again before leaving out of the room a second time.
But Spike the Bulldog punished by her, she kicked him out.
During Nancy's absence, Jerry once again took advantage of the situation and called a bunch of cats who invaded her room to torture Tom. Things for Tom took a turn for the worst, but, Nancy soon returned forcing all 3 cats to flee. Nancy enraged is later shown feeding Tom the castor oil, who he struggles to oppose, but broke out when Jerry Snapped his tail with an iron nutcracker, forcing him to swallow a large spoon full of oil and seconds, Feeling very sick he races out the window and starts to vomit. Jerry laughed enjoying the moment at first, but a large drop of castor oil had later poured down onto his head causing him to vomit as well.
She made a cameo appearance in the Tom & Jerry Tales episode Don't Bring Your Pet to School Day, where she is shown bringing Tom into her elementary School with him looking more annoyed than he did in 1943. She then informs him to behave or they will not win the gold Star for the best pet.
Tom, however, is unamused with this competition and went as far as to remove his bow and hairdo that Nancy gave him off-screen before the episode began. Tom then gets greeted by Bartholomew J. Bunny, who begins to shake his hand while talking in a strange accent, which gets Tom even more annoyed. He then sees Jerry being transported by a cage by Nancy's classmate and friend Bobby. Nancy fawns at the little mouse, and claims to him as being adorable. Tom is amused and continues to eye Jerry, on both revenge (Mostly for humiliating him In 1943, to the other cats, and having him drink castor oil), and hunger (Mostly cause of him always wanting to eat him of course.), he then remembers that Bartholomew is still shaking his hand. Finally snapping, Tom grabs a Mace from out of nowhere and strikes the Bunny in an unknown part, and goes after Jerry causing him to shriek in panic.
He is stopped by Nancy, who is outraged on his behavior and demands that he apologize to him at once. Bobby holds Jerry in front waiting for Tom's answer. At first, Tom doesn't reply or do anything. Nancy insisted again, forcing Tom to kiss Jerry's head in humiliation and annoyance. He then does so twice (Mostly due to him enjoying the taste) and later begins to suck on his head. He then eats the little brown mouse whole but is tossed on the floor by an angry Nancy. "SPIT HIM OUT!!!" She ordered, slamming him on the floor multiple times until he finally coughed him up. Nancy than drags the naughty Tom Cat away, and warns that If they don't win the star, she will take him back to the pound.
Horrible images of the pound haunted Tom, causing him to gulp violently. It wasn't long before he was tossed back to his chair, where Bartholomew is shown with 3 large bumps on his head dazed from the pain. Nancy than points at Tom's Nose and demands him to stay put and be nice to the other animals. Tom shows a hysterical marking the words, "Yes Ma'am" In his eyes. Jerry like back in 1943, strikes again and begins to torment Tom, with a drawing of him in the toilet. Tom furious gets up, but Jerry points back to Nancy, forcing him to sit back down in a cowardly way, despite her not shown when he points.
Jerry than swallows a red apple whole, and goes over where Tom is seated spitting a large number of apple seeds in his face in a machine gun firing rate. Tom beginning to lose his temper, starts to growl. Jerry responded by spitting one more in his face, which caused him to snap, but Jerry points to Nancy again doing her work causing Tom to cower in his chair again.
Jerry then unleashes a frog and escapes the room with Tom pursuing in a panic state. He follows the 2 into the locker room, where he attempts to catch the frog, only to be suckered by Jerry again. Before Tom could react the frog burped a third time, causing him to fly into the locker. Jerry arrives with dirty gym clothes and begins to pack the locker leaving Tom locked up inside. A chase occurs throughout the entire school until it reaches the playground where Tom finally has both pets cornered. At one point he snatches the frog, but Nancy arrives and demands to know what he has in his paw.
Tom on the verge of panic, took drastic measures and ate the frog, turning around facing Nancy grinning he had nothing. Nancy more angry, than disappointing grabs his tail and storms for the classroom revealing that they were next, which meant she had to search the whole school for him. During the presentation, Jerry returns and torments Tom, again with releasing several of the other students' pets. The ants later crawl into Tom's fur making him scratch all over. The Frog jumped again, and soon or later Tom found himself caught in the Globe. "WHAT ARE YOU DOING?!!" Nancy cried, with Jerry laughing onto the Ant farm.
The Fire ants in his fur combined with the frog in his stomach caused Tom to do insane tricks with Jerry still laughing in amusement. The Crowd, however, enjoyed the performance and applauded Tom, even with Jerry joining in the applause. and Tom is shown In Nancy's arms with the gold star. "You may not be the nicest cat, but you at least got the gold star for being the best dancer," Nancy said in her final words before the episode ended, marking the end of her appearance in the Tom & Jerry series.