The legislators, who met for the first time since the formation of the new government, elected Vikho-O Yhoshu of the NDPP as the new speaker.
In the 60-member Assembly, 33 votes were cast in favour of the confidence motion and 26 against it. Barring the speaker, all 59 legislators signed a register to cast their vote for the motion today.
Of the 33 lawmakers that voted in favour of the Rio government, 17 were NDPP members, 12 were of the BJP, two of the NPP, one was a JDU lawmaker and another was an Independent legislator.
Mr Yhoshu had served as an MLA for three terms in the past. He represents the southern Angami-I constituency.
The chief minister, along with 10 other ministers, were administered the oath of office by Governor P B Acharya on March 8.
Mr Acharya had asked the newly-elected chief minister to prove his majority on the floor of the House by March 16.