Chollet faces confirmation difficulties, as Republican Sen. Tommy Tuberville has placed holds on Pentagon nominees over the department's abortion policy.
A memorial service for Colin L. Powell, the retired Army general and former secretary of state who died on Monday, will be held Nov. 5 at Washington National Cathedral.
Powell, who died Monday at age 84, appeared before the United Nations Security Council to provide justification for military action against Iraqi dictator Saddam Hussein, which he later acknowledged was a mistake.
President Joe Biden is set to nominate the chief executive of the U.S.-Russia Foundation and a former National Security Council official on Russia to be the assistant secretary of defense for international security affairs on Tuesday.
The Senate was poised to confirm Colin Kahl to be the undersecretary of defense for policy as two Republicans were expected to be absent for a pair of votes due to family emergencies.
The U.S. Senate on Wednesday advanced the nomination of Colin Kahl to be undersecretary of defense for policy, with Vice President Kamala Harris casting the tie-breaking vote.