Is there a permission that will make people able to change only their OWN nickname and not others nicknames?Because essentials.nick makes you able to change the nickname of everyone. Thank you.
essentials.nick should only give the person access to the command. Try checking your permission for the group or some thing. here is the reference for the essentials permission nodes http://wiki.ess3.net/wiki/Command_Reference
essentials.nick will only allow for people to change their own name. essentials.nick.color or essentials.nick.format will give the players more customizing options. To allow players to change other peoples nicknames they must have the permission essentials.nick.others