Welcome to Allnurses!
The NCLEX exam is just one step in the process of licensure in the US. If you know what state you are going to be living in, I suggest you check the website of that state's Board of Nursing (there are links to all the state BONs at the bottom of every page of this website) and look for the requirements for foreign graduates, or contact the BON directly if the info on the website isn't clear to you. Your nursing education will have to be evaluated and found to be equivalent to US nursing education before you'll be authorized to write the NCLEX and that and the required background check(s) can be a lengthy process.
Best wishes for your journey!