Nance is an intelligence and foreign policy analyst who frequently discusses the history, personalities, and organization of jihadi radicalization and al-Qaeda and the Islamic State of Iraq and Levant (ISIS), Southwest Asian and African terror groups, as well as counterinsurgency and asymmetric warfare.

[2] He has learned Arabic and is active in the field of national security policy[3] particularly, in anti- and counter-terrorism intelligence, terrorist strategy and tactics, torture and counter-ideology in combating Islamic extremism.

[5] In 2014, he founded and became the executive director of the Terror Asymmetrics Project on Strategy, Tactics and Radical Ideologies (TAPSTRI), a Hudson, New York–based think tank.

He studied Spanish, French, and Latin, and took advantage of free classes in Russian and Chinese offered at South Philadelphia High School on Saturdays.

[2] Nance took part in combat operations that occurred after the 1983 Beirut barracks bombings, was peripherally involved with the 1986 United States bombing of Libya, served on USS Wainwright during Operation Praying Mantis and was aboard during the sinking of the Iranian missile boat Joshan, served on USS Tripoli during the Gulf War, and assisted during a Banja Luka, Bosnia air strike.

[18][19][20] In an interview with Michael Harriot of The Guardian, Nance alluded to African-American military aviator Eugene Bullard's service in the French Foreign Legion to his service in Ukraine, hoping to inspire "African Americans and young Americans who have been in the military" and describing the International Legion as "the pantheon of the defense of democracy in the defense of Ukraine".

[2][17] Subsequently, Nance served as an intelligence and security contractor in Iraq, Afghanistan, the United Arab Emirates and North Africa.

[24] Nance now directs a think tank that he founded, the "Terror Asymmetrics Project on Strategy, Tactics and Radical Ideologies", which analyzes counterterrorism.

[2][14] Nance is also a member of the advisory board of directors for the International Spy Museum in Washington, D.C.[17] On March 22, 2019, hours before Attorney General William Barr's controversial letter about the Mueller Report on the 2016 Trump campaign and its connections to Russia was released, Nance said the report could reveal treason exceeding that of Benedict Arnold.