Capitalise first letter of USER_NICENAME?

How would you go about capitalising the first letter of each USER_NICENAME?

I am using a multi-author blog and would like each new FB update to notify our readers of who has written the article. At the moment this is not feasible as I have to edit the automatic FB posts to capitalise our authors’ names.

In User settings, the first letter of the users’ names have all been capitalised. Is there something I would need to change in the database itself, or is this something that could maybe be added on to the plugin?

https://www.ads-software.com/plugins/facebook-auto-publish/