The only way (as I know) to get NX are by buying one of these game cards: (Korea) Gtcard, (Korea) Teencash, (Korea) Oncash card, (Korea) Nexon Card, or a Korea Booknlife card.
Step 1: Enter your username and password, then click login:
Step 2: Click recharge cash on the top of the menu:
Step 3: Click the recharge button next to your current Nexon balance:
Step 4: Check all boxes to agree on the terms of services.
Step 5:Select the type of card you plan to use. If you bought a regular Nexon card, please make sure to click “Nexon card” at the top left of this image. If you can’t type the PIN in the form, please use IE or Chrome as your internet browser.
Step 6: Select the amount you want to purchase.
Step 7: Input card pin and follow item 2, 3, 4 below to complete the
Step 8: If you get this pop-up, then congrats you have gotten your NX!
Credits go to CN-USA for the guide, or to where ever they acquired this from.
I wont list the sites on where you buy the game cards as these sites are very easy to find with a simple google search. Also, if you get scammed or ripped-off in any way while trying to buy a game card it’s not my fault.