A muster roll dated October 15, 1861 makes the comment that Nevin's promotion was made "…by desire of the major (Oscar Veniah Dayton) and every line officer.
Nevin's promotion from captain to lieutenant colonel appears to have been a reward for good service while the regiment was encamped at Tennallytown, DC.
Nevin acted in the capacity of senior officer for several weeks before handing in his resignation to Peck who forwarded it to Major General McClellan with the recommendation that it be rejected.
However, in April 1863 his sentence was disapproved by the Secretary of War, Edwin M. Stanton and he was released from arrest, and restored to his command.
After the removal of McClellan from command of the Army of the Potomac a conspiracy against Nevin by his superior officers was discovered, and Governor Seymour was "…called upon to see that justice was done to one of whose services the State might well be proud.