One of the playable racers in the game is the Iron Checkpoint Crate, which was added in response to a popular meme post on the r/CrashBandicoot subreddit.

Geary's Legendary Skin, Beenox Robot Geary, is based on a mascot used by Beenox in opening logos for movie-licensed games in the 2000s. It was added in response to high demand from fans for Geary to receive a legendary skin, as he was the only base game character without one for a very long period.

On the character designer for Nitros Oxide in Crash Team Racing, Bob Rafei's website, he has a portfolio containing various works sorted by game. In the Crash Team Racing folder of the site, there is an image of a blue hippo in an aviator suit named "trippo.jpg". According to Rafei in 2017, this character was designed as a mascot for an airline search engine during the dot-com boom, but was placed in the CTR folder of the site by mistake. However, in the time between the image's discovery and the clarification, the image was spread online as if it was a lost Crash Bandicoot character, gaining the accepted name of "Fasty" through unknown means.

In Crash Team Racing: Nitro Fueled, the character Hasty the Moose, one of two completely original characters alongside King Chicken, was inspired by the myth of "Fasty", with a similar body build; face; outfit; and name in both meaning and spelling.

Upon the release of Rilla Roo as a DLC character in Crash Team Racing: Nitro-Fueled, the model of the character was heavily criticized for how far it strayed from his original model in Crash Bash, particularly the presence of a large beard and chin on his face, with many fans editing mockups of a more faithful Rilla Roo. In the game's final DLC update, a "fixed" version of Rilla Roo would be provided - however, rather than serving as a skin for, or replacing the original, Rilla Roo, this new Rilla Roo would be made a separate character titled "Fixed Rilla Roo", with his own animations and exotic skins. His victory podium animation has him stop to check his face, and then sigh in relief as a meta-joke.

In Crash Team Racing: Nitro-Fueled, King Chicken's name had been uncovered through datamines months before his release. These datamines show that the character's name was very briefly changed to "King Paul III" (a pun on "poultry") before being reverted back to the earlier name for the character's official release.

According to Crash Team Racing Nitro-Fueled art director Jason Godbout, when the Crash Nitro Kart bosses were being redesigned, extra care was given to Nash the Shark so he would be "so awesome" that he becomes "the character that everyone's gonna want to play [as]". Godbout believed that Nash went from being "okay, but unappealing" in his Nitro Kart iteration to being his personal favorite character in Nitro-Fueled due to the redesign efforts.

The Lumberjack Lab Assistant enemy from Crash Bandicoot 2: Cortex Strikes Back is usually portrayed wearing a red hat and shirt with blue overalls. This design is used for his NPC role in the Dragon Mines stage of Crash Team Racing Nitro-Fueled, but as a skin for the playable version of the Lab Assistant in that game, his colors are inverted, possibly to downplay potential similarities to Mario.

Unused files in the game suggest Willie Wumpa Cheeks from Crash Tag Team Racing, Ripto from the Spyro series and the Sorceress from Spyro: Year of the Dragon were once planned to be added to the game as playable characters. These files were originally found in 2019 by a dataminer following the start of the first Grand Prix and featured almost every character that would later be added to the game.

According to the Willy the Wombat production bible, Dr. Neo Cortex was born in the circus and physically abused by clowns. Since then, anything that involves clowns makes Cortex enraged.

In games like Crash Team Racing Nitro-Fueled and Crash Team Rumble, Cortex has an unlockable skin in which he is dressed up like a clown. Humorously in Nitro-Fueled, Cortex’s victory animation features him with a dismal glare.

The July 2019 version 1.07 update renamed several alternate skins, likely due to unintended racial connotations caused by the original names:

• Watermelon Tawna is renamed Summertime Tawna.
• White Tawna is renamed White Tiger Tawna.
• Black Zem is renamed Solar Flare Zem.
• White N.Tropy is renamed Carbon Fiber N.Tropy.
• Red Papu Papu is renamed Crimson Papu Papu.

While most of the affected costumes were renamed due to the use of the terms "white" and "black," which are also common racial designations, Watermelon Tawna and Red Papu Papu's names were changed due to them invoking racial stereotypes in combination with their designs. Watermelon Tawna depicts her with brown fur, dark hair, and a watermelon-themed shirt; the juxtaposition of these traits in combination with her costume's name was likely deemed too evocative of anti-black stereotypes depicting African-Americans as having insatiable appetites for watermelons. Meanwhile, since Papu Papu is an indigenous Polynesian character, attaching the term "red" to his costume's name was likely deemed too similar to the offensive practice of describing Native Americans as "red."

The developers of Crash Team Racing Nitro-Fueled were informed ahead of time that the game's post-launch support would be limited. Very little content was thought of, and none was worked on, for grands prix that didn't make it to release. Creative director Thomas Wilson stated the only scrapped grand prix concept he recalls is "Heroes vs. Villains", a superhero parody grand prix compared to the animated film Megamind, which would have featured a course in a "retro-futuristic" city and superhero and supervillain outfits for the racers.

When playing as Penta Penguin, he will occasionally say "Penguin Yay 1". This is a reference to a glitch in the original NTSC version of Crash Team Racing where his voice acting was left unfinished, and the voice of programmer Gavin James saying "Penguin Yay 1" and "Penguin Yay 2" were accidentally released with that version of the game as placeholder sounds.