Its very easy to add a nickname or maiden name on your facebook profile.All you need to do is add an alternative name to your profile. To do so you have to follow few steps.
Step 1: Go to your facebook profile page and click settings menu from top right and click Account Settings.
Step 3: Now add your alternative nickname in the alternative name field.
Step 5: Now enter your password and click Save Changes.
You are done. Now your nickname will be shown on your profile and also in the search field.