Here is the full list of all 27 Nickelodeon: Kart Racers achievements worth 1,000 gamerscore.
Unlock every upgrade in the store.
Win all Cups in easy mode.
Win all Cups in Normal mode.
Win 9 victory laps.
Activate the Slime in all the locations.
Break 5 objects in a single race using boost.
Compete 10 times in each Arena mode.
Win a Cup in easy mode.
Win a Cup in Normal mode.
Win all Cups in Expert mode.
Put in the miles on the jetski.
Win at the last second in Grand Prix Mode.
Co-operative special attack for the first time.
Win with all racers.
Play as each racer at least once.
Use custom power ups for all the racers.
Compete in the Arena for the first time.
Take down at least 3 opponents in a single race.
Win a Cup in Expert mode.
Beat your record for first time.
Modify your kart for the first time.
Win a victory lap.
Find a shortcut.
Win your first race.
Use a custom power up for the first time.
Activate the Slime valve for the first time.
Use boost for the first time.