Following The Basic School and the Infantry Officer Course, Lieutenant Nastase was assigned to 1st Battalion, 5th Marines, 1st Marine Division at Camp Pendleton, California in March 1990. During this tour, Colonel Nastase served as a rifle platoon commander, participating in Operations DESERT SHIELD and DESERT STORM as a member of Task Force Ripper. He served as the S-3 Training Officer during a subsequent deployment to Okinawa and the Republic of Korea. Additionally, he served in Weapons Company as the heavy weapons platoon commander and company executive officer.

In February, 1993, First Lieutenant Nastase transferred to The Basic School, Quantico, Virginia and was assigned as the Infantry Unit Leader, Enlisted Instructor Company. After promotion to Captain, he served as a Staff Platoon Commander for Company C and Company A, as the Assistant Operations Officer, TBS, and as an instructor in the Offensive Tactics Section. In July 1996, he received orders to attend the Marine Corps Amphibious Warfare School, Quantico, Virginia.

Upon completion of career level school in May 1997, Captain Nastase reported to 2d Marine Division, Camp Lejeune, North Carolina for duty as Commanding Officer, Company E, 2d Battalion, 6th Marines. Upon completing a deployment with E/2/6 to Okinawa and Korea as part of the Unit Deployment Program, he was assigned as the S-3A, 6th Marines. In January, 1999, Captain Nastase assumed command of Headquarters Company, Headquarters Battalion, 2d Marine Division and deployed to Assiros, Greece with 2d MEB for NATO Exercise Dynamic Mix 2000.

In July 2000, Major Nastase was assigned as Operations Officer, Headquarters and Service Battalion, Marine Corps Base, Quantico Virginia. From February-June, 2003, Major Nastase was assigned as Operations Officer, Enduring Freedom Combat Assessment Team (EFCAT) serving with MARCENT in Bahrain, Kuwait, and Iraq during Operation IRAQI FREEDOM I. Upon return from the EFCAT mission, Colonel Nastase attended the Marine Corps Command and Staff College where he was a distinguished graduate, receiving a Masters of Science degree in Military Studies. In 2004, he also completed a Masters of Education degree from Old Dominion University.

In June 2004, Major Nastase reported to 1st Marine Division, Camp Pendleton, CA for duty as Operations Officer, 5th Marines. In September 2004, he led the advance element of 5th Marines personnel to Ar Ramadi, Iraq in support of 1st Marine Division as the Deputy Director, Iraqi Security Forces (ISF) during Operation IRAQI FREEDOM II. Returning to Iraq in January 2006, Lieutenant Colonel Nastase served as Operations Officer, Regimental Combat Team 5, in Al Fallujah, Iraq during Operation IRAQI FREEDOM 05-07.

In October, 2006, Lieutenant Colonel Nastase assumed duties as Commanding Officer, 3d Battalion, 3d Marines, Kaneohe Bay, HI. From July 2007 through February 2008, he led Task Force 3/3 in Al Fallujah, Iraq during Operation IRAQI FREEDOM 06-08. Upon relinquishing command of 3/3 in June 2008, he served as Executive Officer, 3d Marines until his subsequent transfer in January 2009 to attend the NATO Defense College, Rome, Italy.

Upon completion of Top Level School, Lieutenant Colonel Nastase joined US European Command, Stuttgart, Germany, where he served in the Current Actions Branch (J33) and subsequently as the Chief, Joint Training Readiness and Exercise Division (J37). Colonel Nastase assumed command of 3d Marine Regiment on 23 June 2011.

Colonel Nastase’s personal awards include the Bronze Star Medal with two gold stars in lieu of third award, Meritorious Service Medal with gold star, Navy-Marine Corps Commendation Medal with gold star, Navy-Marine Corps Achievement Medal with gold star, and the Combat Action Ribbon with gold star.