Yesterday, the Supreme Court ordered that the House of Representatives be reinstated and directed the President to appoint Mr Deuba as new prime minister on Tuesday.
The five-member Constitutional Bench led by Chief Justice Cholendra Shumsher Rana said that Mr Oli's claim to the post of prime minister was unconstitutional.
The house was dissolved on May 22 by President Bhandari over the recommendation of Prime Minister KP Sharma Oli, but it was challenged by an alliance of the opposition parties and others at the Supreme Court.
Deuba had served as Nepal's Prime Minister from June 2017–February 2018, June 2004–February 2005, July 2001–October 2002 and September 1995–March 1997.
Deuba will have to win a vote of confidence from the House within 30 days of his appointment as the Prime Minister, as per constitutional norms.