Here are 10 developments in this big story:
Nitish Kumar and his ministers were administered the oath of office at Raj Bhavan by Governor Phagu Chauhan, a day after he staked claim to form the new government. The 69-year-old has had a continuous run since November, 2005. There was a short break in 2014-15, when the post was occupied by Jitan Ram Manjhi.
Vijendra Yadav, Vijay Choudhary, Ashok Choudhary, Mewalal Choudhary, and Sheela Mandal from Nitish Kumar's Janata Dal United and BJP leaders Mangal Pandey and Rampreet Paswan are among the 14 ministers inducted in the new cabinet. Santosh Manjhi of the Hindustani Awam Morcha or the HAM, and Mukesh Mallah of the Vikassheel Insaan Party (VIP) are on the list too.
"Congratulations to @NitishKumar Ji on taking oath as Bihar's CM. I also congratulate all those who took oath as Ministers in the Bihar Government. The NDA family will work together for the progress of Bihar. I assure all possible support from the Centre for the welfare of Bihar," Prime Minister Narendra Modi tweeted.
Nitish Kumar was formally named the leader of the state's ruling alliance at a meeting of the NDA MLAs on Sunday. The meeting was also attended by senior BJP leader and Defence Minister Rajnath Singh, the party's state in-charge Bhupendra Yadav and election in-charge Devendra Fadnavis.
At the meeting, Nitish Kumar had proposed to turn over the top post to the BJP, but the party had decided to stick to the pre-election deal that Mr Kumar retain the post, the BJP spokesperson said today.
In a first in the state, the BJP, however, insisted on having two deputies for Mr Kumar. Two deputies are usually a hallmark of BJP-ruled states. In the backdrop of anti-incumbency against Mr Kumar and the opposition allegations of the government's mishandling of many issues, the BJP said it was meant to keep the emphasis on governance and take the state forward.
The selection of a woman deputy Chief Minister -- Bettiah MLA Renu Devi --is seen as a signal for the woman's mandate, which has been crucial for the BJP in almost every victory.
Sushil Kumar Modi -- who was Nitish Kumar's deputy in the last term and the tallest BJP leader in the state -- is likely to have a Central assignment soon. Sources said he is likely to be given with a berth in the Prime Minister Narenrdra Modi's ministry. "The BJP and the Sangh Parivar gave me so much in the political life of 40 years. I will discharge the responsibility that will be given to me. No one can take away the post of the party worker," Sushil Modi tweeted on Sunday.
"Congratulations to Nitish Kumar Ji for becoming the Chief Minister again. I hope the government will complete its tenure and you will continue to be the Chief Minister of NDA," tweeted Chirag Paswan. The Lok Janashakti Party leader who rebelled against Mr Kumar's leadership and contested solo is seen as a key reason of the poor performance of Mr Kumar's JDU.
The Rashtriya Janata Dal and its chief Tejashwi Yadav boycotted the oath ceremony. "Best wishes to respected Nitish Kumar ji for being 'nominated' as Chief Minister. I hope instead of pursuing his ambitions, he will fulfill the aspirations of the public and will fulfill NDA's promise of 19 lakh jobs, and will make positive issues like employment, health, income generation, irrigation his priority," the 31-year-old tweeted.