Crash Team Racing Nitro-Fueled platinum trophy is a tough one. It will require more skills than luck and you need to master almost every track, get all collectibles, which is going to be a tough task.
One of the hardest trophies/achievements in the game is “Galaxy’s Fastest” which is also needed in order to unlock Nitrous Oxide. To get this trophy/achievement, you will need to fulfill the following requirements in the game.
This requires you to get 100% completion in the Adventure Mode. This is not going to be as easy as it sounds. You don’t just need to get 100% completion but defeat Nitros Oxide a second time for Galaxy’s Fastest trophy/achievement.
To unlock the Gem Cups, you will first need to defeat the last boss and then finish any CTR challenges. You can find the Gem Cup in a separate area called Gem Stone Valley. You also need to win on the two bonus tracks to quality which includes Slide Coliseum and Turbo Track.
Once you have received 100% completion in the Adventure mode, Nitrous Oxide will be available to challenge again. Defeating him the second time is harder but if you have mastered every shortcut, learned to rush through a level with the drifting bonus, then you should be able to beat him and unlock Galaxy’s Fastest trophy/achievement in the game.