In June 1942, Nichols was again summoned by Marshall, this time to Washington, D.C. Marshall had recently been appointed as district engineer of the new Manhattan Engineer District (MED), and had received authorization to staff it by drawing on officers and civilians working for the Syracuse Engineer District, which was now winding down as the major part of its construction program was nearing completion.
Незадолго до этого Маршалл был назначен окружным инженером вновь образовывавшегося «Манхэттенского инженерного округа» ("Manhattan Engineer District", впоследствии переименованном в Манхэттенский проект) и получил одобрение укомплектовать его офицерами и гражданскими из Округа Сиракьюз, работы по которому раз подходили к завершению.