Hit the Slime-filled race tracks with Nickelodeon Kart Racers! Select a racer from one of your favorite Nickelodeon series, including SpongeBob, Patrick, and Sandy from SpongeBob SquarePants, Leonardo, Raphael, Michelangelo, and Donatello from Teenage Mutant Ninja Turtles, Arnold and Helga from Hey Arnold!, & Angelica, Tommy and Reptar from Rugrats. Race your friends in up to 4-player local multiplayer or check out the Battle Arena for a variety of challenges.
Go to https://www.xbox.com
Login to your account
Hover over your account link (the top right of the screen) a menu will appear, click on the "Redeem Code" button.
On the next page, click "Redeem"
Enter your code
Click "Confirm" again to assign the key to your account.