You can change your nickname by either purchasing the VIP membership or purchasing the One-time purchase Change Nickname item.
You can purchase :
1. the VIP membership by clicking the crown icon located at the right corner of the screen in the Discover tab.
2. the One-time purchase Change Nickname Item by going to your profile, clicking your nickname, entering a nickname and clicking 'Change nickname'.
You can change your nickname permanently once with the One time purchase Change Nickname Item.
You can also change your nickname numerous times by purchasing the VIP membership, but unsubscribing from the membership will change your nickname to what it was originally.
Please be advised, inappropriate nicknames will be rejected.