Prosecutors have also charged al-Nashiri over a failed attack on another US warship, the USS The Sullivans, in Aden in January 2000 and an attack on the SS Limburg, a French supertanker, in the Gulf of Aden in October 2002.
Hartmann, a legal adviser to the US military tribunal system, said the allegations include conspiracy to violate laws of war, murder, treachery, terrorism, destruction of property and intentionally causing serious bodily injury.
"Five of the eight charges carry the maximum penalty of death," he said.
The CIA has said it used waterboarding, a form of harsh interrogation that simulates drowning, on al-Nashiri, and he has alleged he was tortured.
Hartmann said the way the evidence was gathered would be considered at al-Nashiri's tribunal.
"We will look at the evidence, all of the evidence that is associated with the case," Hartmann said.
"While there has been an admission that there was waterboarding, there may well be other evidence in the case."
That's not ... necessarily the only part of evidence in the case."
The US claims that al-Nashiri was al-Qaeda's operations chief in the Arabian peninsula until his capture in 2002.
He has met Osama bin Laden, the head of al-Qaeda, several times, US officials allege.
If the charges are approved, an initial hearing could take place within 30 days.
Human rights groups have condemned waterboarding as torture and the military tribunals, which are used to try inmates at the Guantanamo Bay prison in Cuba, as unfair.
Al-Nashiri is one of 14 "high value" detainees held at Guantanamo Bay who are regarded as particularly significant by US officials.