PortalPermissions is a simple plugin that blocks players from creating nether portals unless they have permission.
This plugin was originally made as part of a plugin request and I decided to publish it so that it can help out other people.
The plugin is very simple to use with only 1 command 2 permission nodes:
/portalreload - Reloads the plugins configuration file. (requires portalpermissions.reload)
portalpermissions.create - Allows the player to create a nether portal.
Source code can be found here.