How will I add my mother's maiden name to my marriage license?

Your question is a bit unclear.  If you have a "husband," your marriage "license" is long-since final and submitted.  Perhaps you mean marriage certificate, but if so Nevada cannot do anything about it if you were married in California (you would have to amend it there).  Otherwise, you could file a formal name change application; if you want to read about those, you can look at the forms at the Nevada self-help center website, http://www.familylawselfhelpcenter.org/self-help, or hire counsel.