Dear aspirant

I think your questions is wrong, chief minister are for any state not for whole India.

Prime Minister of India is the head of government of the Republic of India. And chief minster is head of government in any state.

If your question is first prime minister of india then Jawaharlal Nehru was the India's first prime minister, serving as prime minister of the Dominion of India from 15 August 1947 until 26 January 1950, and thereafter of the Republic of India until his death in May 1964.

Hope this information helps you

All the best