Vice Admiral Nichols' duty at sea includes tours in Attack Squadron 145 (VA-145), Attack Squadron 165 (VA-165) and Attack Squadron 196 (VA-196). He commanded Attack Squadron 196 (VA-196) on board USS "Independence" in 1990-1991 during Operation Desert Shield and Carrier Air Wing Two at NAS Miramar, California and embarked on board USS "Constellation" in 1994-1995 during deployment to the Persian Gulf in support of Operation Southern Watch. He commanded Carrier Group One headquartered at NAS North Island in San Diego, California from July 2000 until November 2001. He then assumed the duties as Commander, United States Naval Forces Central Command (COMUSNAVCENT) and Commander, United States Fifth Fleet at Naval Support Activity Bahrain in Manama, Bahrain from October 2003 until November 2005.