If you need to change your NCI password due to login or other technical issues you can follow these instructions from the IT Support Hub to do so.
If you have just forgotten your password there are different guidelines which can be found here.
After changing your password it is advised to wait 5/10 minutes before logging in again with your new password. If it still does not work it may help to clear your cache in your browser history.
If login issues persist after all the above steps you can "Submit a Request" at the top right corner of the IT Support Hub.