Nutty has rabies, as is mentioned in the "Collect Them All" section of the First Blood DVD. This might be seen in his debut episode, as he foams at the mouth when trying to get a candy bar, and in the False Alarm episode, where his mouth is foaming while he is lying on the hospital bed.
After Nutty gets killed in A Sight for Sore Eyes, Russell mistakes his googly eye for his contact lens. After putting it on, Russell sees his kite's ribbons as being made of candy. This is evidence that Nutty may see everything as candy because of his eyes, meaning that his problem is at least partially physical, instead of purely psychological as was previously believed.
Nutty can be seen in episodes with parts of his candy wardrobe not appearing or falling off.
In the False Alarm episode, after Nutty leaves the rehab center, he no longer has his lazy eye, indicating that it is probably a physical condition caused by his high sugar intake.
Nutty has heterochromia (two different eye colors), having one black eye and one googly green eye.
Nutty receives an injury in every episode he stars in, except for Sweet Ride and Going Out With a Bang, though he does get constipated in the latter episode, he never received any physical injuries like in his other starring roles.
Nutty is the character who gets the most medical treatments(most of which are caused by his candy addiction):
If you choose Nutty in the Vision-O-Rama feature in the Third Strike DVD, the movie theater's screen will show a "shaky" Spin Fun Knowin' Ya, a reference of Nutty's jittery nature.
Nutty is one of the few characters to be disliked by both characters of a duo other than Lifty and Shifty, the other duo being Pop and Cub due to his actions in A Sucker for Love.
He has interacted with almost every character, except for Mr. Pickels.
Despite Lifty and Shifty being known for their thefts, Nutty is another character that commits crimes, and much like them, he always gets a comeuppance for his actions (with the exception of the final one listed):
In Sweet Ride, he stalks and chases down Cuddles, wanting his ice cream.
In Icy You, he attempts to steal sweets from Lumpy's store before gulping down gallons of unpaid slushies.
In A Sucker for Love, he steals Cub's lollipop, damages a gumball machine, and tries to steal a box of chocolates. He also kills Lumpy and is sent to jail (in his imagination).
In Concrete Solution, he steals a bag of sugar from the Happy Tree Café and a bag of cement from a construction site, mistaking it for said bag of sugar.
Interestingly, he (technically) stole Lifty and Shifty's magic lamp in As You Wish and a candy cane from their van (intending to steal video games) in the False Alarm episode while Lifty and Shifty only stole his snow cone in Swelter Skelter, this makes Nutty the only character to steal from Lifty and Shifty more often than the other way around.
His name comes from both his manic personality and the stereotype that squirrels love to eat nuts (which is ironic as Nutty has yet to eat a nut in the series).
Nutty, unlike most characters, does not have Pac-Man-shaped pupils (though his googly eye has a Pac-Man-shaped pupil in most episodes).
Nutty's concept art shows that he was originally supposed to have even more candy on his body and in different places.
The all-day sucker on his face would be slightly redesigned in internet season 4. It used to have multiple stripes in different colors, but the stripes were decreased for a simpler appearance.
There is a slight possibility that the reason Nutty never eats the candy on his body when he is desperate for food (like in Dunce Upon a Time, where he and Giggles are starving) is because he thinks he will be naked, since he wears candy like clothes, as shown in Chew Said a Mouthful.
The only time he ate his "clothes" is in Nuttin' Wrong with Candy, but this is most likely due to the fact it was his first appearance.
In the TV series, Lumpy, Flaky, Russell, Toothy, Mime, The Mole and Giggles appear in all of his starring roles. Flaky, Toothy, and Mime die in both episodes, Lumpy, Russell, and The Mole die in only one episode, while Giggles survives both episodes.
Nutty is one of the few characters who star in two TV episodes. The others are Handy, Flaky, and Mime.
Nutty's googly eye sometimes switches sides on his face, either right or left, with the same thing happening with the candy on his body; much like Lumpy's antlers, Lammy's bow, Flippy's beret, Russell's eyepatch and hook, The Mole's mole, Handy's tools, Sniffles' pocket protector, and Cub's diaper pin.
Nutty, Sniffles, and Russell are the only characters to debut in a solo episode.
Nutty is one of seven characters not to have the same kind of eyes as the other characters. The other six characters are Lumpy, Cub, The Mole, Lifty & Shifty (from the TV series onwards), and Mr. Pickels.
Out of the characters who rarely survive, Nutty is one of the few characters to star in a sole cause episode and survive. The others are Cub and Disco Bear.