Nagaland Governor P.B. Acharya administered the oath of office and secrecy to Rio, Patton and 10 other cabinet ministers.
Quitting the party, he had said: "I have been left with no option but to resign from the NPF in accordance of the wishes of the people and in the greater interest of the masses in collective endeavour to bring an early political solution". Mr Rio said that his Government has committed in the manifesto that we will remove VIP culture from Nagaland and will ensure that the citizens of the State are the real VIPs. The cabinet reiterated that the government would play the role of a facilitator in Naga peace process, and urged Naga groups that haven't yet done so to join ongoing negotiations.
By and large, the Nagaland Legislative Assembly poll has pronounced a fractured verdict.
The ruling alliance has 18 legislators of Nationalist Democratic Progressive Party (NDPP) - a new party Rio heads after he broke away from the Naga People's Front - 12 BJP MLAs and has the support of one JD (U) MLA and an Independent.
Outgoing chief minister TR Zeliang resigned on Tuesday.
The NPF won 27 seats in the 60-member Nagaland Assembly.
The governor has asked the newly-elected chief minister to prove his majority on the floor of the House by March 16.
The BJP-NDPP combine that bagged 30 seats enjoyed the support of one JD (U) legislator and an Independent.
The NPP had contested the Assembly election in alliance with the Naga People's Front (NPF), but after the declaration of the results on March 3, it had made a decision to support the NDPP-BJP alliance. In a first, Rio took the oath as the new Chief Minister in full public view at the Kohima Local Ground along with the council of ministers.
Defence Minister Nirmala Sitharaman, Union minister Kiren Rijiju, BJP president Amit Shah and the party general secretary Ram Madhav were all present at the swearing-in ceremony.
"'We have also chosen to conduct the function at this historic place in honour of the people we are to serve and to also remind ourselves publicly of the responsibilities that lie upon our shoulders", the chief minister said.