"Delhi should get full statehood and we will support it," Kumar said after the meeting held at the secretariat here.
The meet comes a day after Kumar had a meeting with Prime Minister Narendra Modi.
The Bihar Chief Minister had come to congratulate Kejriwal and AAP MLAs for their victory in Delhi assembly polls.
"Nitishji came to congratulate us for our victory in Delhi. We had invited him for lunch," Kejriwal said.
Kejriwal denied having any political talks with Kumar. He also declined to comment on reports of AAP support to JD(U) for upcoming Bihar assembly election.
"We had met before at Rashtrapati Bhawan, which was a coincidence. Then we had decided to meet in future. I was here so I came to congratulate him and his team," Nitish said.
Nitish also met Congress President Sonia Gandhi today and drove to Tihar jail to see INLD chief Om Prakash Chautala.