Anyone can throw a name out, and many often do, but actual nominees (there are 278 this year) are kept secret for 50 years. Except for the winner, of course.
Actual nominees, according to the Nobel Foundation, must come from these sources:
http://www.nobelprize.org/nomination/peace/
Qualified Nominators
According to the statutes of the Nobel Foundation, a nomination is considered valid if it is submitted by a person who falls within one of the following categories:
Members of national assemblies and governments of states
Members of international courts
University rectors; professors of social sciences, history, philosophy, law and theology; directors of peace research institutes and foreign policy institutes
Persons who have been awarded the Nobel Peace Prize
Board members of organizations that have been awarded the Nobel Peace Prize
Active and former members of the Norwegian Nobel Committee; (proposals by members of the Committee to be submitted no later than at the first meeting of the Committee after February 1)
Former advisers to the Norwegian Nobel Committee
Anyone else is claiming to "nominate" just BS PR.