Trying to update the contact nickname for individual contacts via update multiple contacts doesn't work. You can go through the whole process, but in the end nothing will actually be changed in the contact records. However, organizations can be updated with this method.
Steps: Select individual contacts, update multiple contacts, select a profile with nickname, change nicknames as desired, submit.
Result: Process appears to complete as normal. No change to nicknames. Tested on 5.7.3 on Drupal and Drupal demo (5.12.alpha1)
Note that you can still change the nickname on the contact profile.
It's a very small thing, but can be a bit frustrating because there is no error, so you don't know that your changes haven't taken effect. Does this seems like a bug that should be reported?