The reason why the browser shows this site is not secure is that they aren't using an HTTPS connection to secure the traffic. However, if you are accessing their NX purchase store, you can see that it is a secure connection. The difference between a secured and unsecured is that the traffic would be encrypted by a certificate. My guess is that since the main site is largely informational and does not actually contain any sensitive data, they didn't feel the need to have HTTPS setup.
