How do I reset the nether world on my Minecraft server?
Stop the server
Locate the World box on the main page of the control panel to find your world name

The default name will be world, but your's may be different if the default name was changed.
Navigate to the Files>FTP File Access tab of the control panel

Enter your control panel password and login
Locate the folder titled (name of your world from step 2)_nether
Select this folder and click Rename

Change the name to something else that is not already in use
You can even just add a number or letter on the end of it.
Submit your changes
Start your server
That's it - a new nether world will generate on the next server startup!
Locate the World box on the main page of the control panel to find your world name

The default name will be world, but your's may be different if the default name was changed.
Navigate to the Files>FTP File Access tab of the control panel

Enter your control panel password and login
Locate the folder titled (name of your world from step 2)_nether
Select this folder and click Rename

Change the name to something else that is not already in use
You can even just add a number or letter on the end of it.
Submit your changes
Start your server
That's it - a new nether world will generate on the next server startup!
Updated on: 06/21/2021
Thank you!