In Nitro Nation, you can add more than 1 profile to your device. To switch to another account, go to Garage - Profile - Edit. At the bottom of the screen, you should see other accounts logged in on that device. Tap Load profile, and the game should switch to it. To switch back, repeat these actions.

Note that according to our game's Terms of use, we allow using only 1 account per platform (Android, iOS, Windows).