Why Peace... Nobel Prizes are given for Physics, Chemistry, Physiology, Medicine, Literature, Economics as well as Peace.
181 names were submitted for the 2007 Nobel Peace Prize, 46 of which are organizations. The Nobel Committees in Physics, Chemistry, Physiology or Medicine, Literature and the Prize Committee for Economics each usually receives 250-300 names every year. The names of the nominees cannot be revealed until 50 years later.
http://nobelprize.org/nomination/nomination_facts.html
He may have been nominated and just not won.. We do not know.