Economist Dr. Swarnim Wagle filed his candidacy for the by-election from Tanahun-1 on Monday afternoon.
Vishwanath Bastola proposed him while his candidacy was seconded by Rupak BK Ghimire.
RSP Chairman Rabi Lamichhane was also present during the nomination filing.
Tanahun-1 lay vacant after senior leader of Nepali Congress Ram Chandra Poudel was elected as the president of Nepal on March 9.
Wagle defected to RSP from Nepali Congress to contest the by election to be held on April 23.
