NOTE: Nexon only allows a maximum of 3 accounts to be made from the same ip in a short period of time, so if you try to go more than 3 within a minute, you will be prevented from making accounts for a couple hours...

What you will need:
Google Chrome
Hidden-Field Switcher

Step 1:
Install Chrome, then install the Hidden Field Switcher extension and restart Chrome. Now press the wrench in the upper right corner of chrome and go to Extensions.

You will see "Hidden Field Switcher" and under it will be a check box that says " Allow this extension to run in incognito". Check that box.

Step 2:
To create as many accounts as you want in a row, you need to use "Incognito Mode" so that Nexon does not save cookies. To open a new "Incognito" window, open Chrome and press "Ctrl+Shift+N". A new "Incognito" window will appear.

This is why you need to enable the Hidden Field Viewer extension in Step 1:

Step 3:
Now you want to go to the Nexon Sign-up Page. Before you fill out anything, press "Ctrl+Shift+S". A bunch of new input boxes will appear at the top and bottom of the page. The one you want to be looking at is at the bottom of the page. You will see a bunch of random letters and numbers already entered into it. Hover your cursor over that box. You will see that is is called "idMachineKey". It is the unique id generated by Nexon for your computer. Normally it would stay the same and you would not be able to see it, but we have used Hidden Field Switcher to access it.

Step 4:
Now we can change it and make Nexon think we are on a different computer Go to the last character and change it. Now fill out the signup page normally, enter the CAPTCHA and press "Done". You will see that it will go through.

Step 5:
If you want to make some more accounts, you can press the back button. You will see that most of the fields are still filled in. You will also see that the hidden field at the bottom is gone. Press "Ctrl+Shift+S" to see it again. Again, change the last character to something else (not the same as last time you changed it though or you will need to refresh the page and start over), fill out the fields that got reset, put in a new username and email, and hit "Done" (the CAPTCHA does NOT need to be changed). Repeat Step 5 as many times as you want and there you go, plenty of new accounts.