By Jonathan Stempel, Sarah N. Lynch and Karen Freifeld NEW YORK (Reuters) -U.S. prosecutors charged two Chinese nationals with trying to obstruct the prosecution of Chinese telecommunications company Huawei Technologies Co Ltd, as part of a broader crackdown on what they called efforts to exert unlawful influence in the United States. Chinese nationals Guochun He and Zheng Wang were charged in a criminal complaint dated Oct. 20 and made public on Monday. Court documents did not name the company, but a person familiar with the investigation said they were trying to interfere with the prosecutio…