I'm not for trusting third party sites or software to do generation, though others may feel differently. I do welcome different views on the wiki 
Feel free to register (PM joefox, the wiki admin) and edit, or comment in the talk page.
Feel free to register (PM joefox, the wiki admin) and edit, or comment in the talk page.The bitaddress.org page can be also saved and used in offline mode. To my knowledge it is one of the most popular methods of generating Bitcoin paper wallets. If there is something more popular in the Bitcoin world, then I would recommend using the same method also for your NXT password. There is no need to reinvent the wheel here.