From Patterico, a potential nominee himself, quoting from the LA Times:

Around the same time, Becnel met a woman who was active in anti-violence efforts in Zurich, Switzerland, and took Williams’ campaign to Europe. Zurich, like many California cities, was troubled by gangs, with Somali and other immigrant youths engaged in violence, Becnel said.
She made several trips to Zurich and eventually met the Swiss national legislator Mario Fehr, who would nominate Williams for the Nobel in 2001. Legislators and professors in certain disciplines can nominate Nobel Prize candidates.
“The Nobel Prize nominations really catapulted his name into the media,” Alonso said. “That’s when reporters started calling me.” …
In the meantime, Philip Gasper, an anti-death penalty activist and a professor at Notre Dame de Namur University, a small Catholic school in Belmont, near San Francisco, heard Williams speak via telephone to a UC Berkeley panel and decided to submit more Nobel Peace Prize nominations.
“Barbara and I came up with the idea, and she helped me through the process,” Gasper said.
“All you need to do to nominate is to write a nominating letter to the committee in Norway,” Gasper said.
Gasper’s prime motivation in writing the four-page letter was to save Williams’ life, he said, but he also thought that Williams deserved the prize because “his message has had such resonance with kids in the U.S. and in other countries.”
“I think he has probably saved a few hundred lives, at least,” said Gasper, who has nominated Williams four times for the peace prize.
Brown University English professor William Keach, who is also active in the campaign to end the death penalty, nominated Williams for the Nobel Prize for literature…