Q : Can an individual who has held U nonimmigrant status eventually apply for permanent resident status?

Yes. The individual must have been physically present in the U.S. for a continuous period of at least three years since the date of admission as a U nonimmigrant, and the agency must determine that he individual's continued presence in the country is justified on humanitarian grounds to ensure continuation of a cohesive family, or is otherwise in the best interest of the public.