Let’s see if I can clear things up for you. 
Yes. All you have to do is register a new World of Warcraft account for the region that you want to play in. You can do that on your current Blizzard account (Battle.net account), as it can hold up to 8 different World of Warcraft accounts (licenses).
You can add a starter account for your region of choice here: https://account.blizzard.com/games (scroll down to the Starter Editions section, and select the region after clicking on Create Starter Account).
If you want to upgrade (add the current expansion) or add gametime, you can do so through the US region shop.
Have a few seconds to spare? Let me know how I’m doing!