The Bharat Ratna is the highest civilian award of the Republic of India. It was incorporated in 1954, the award is conferred "in recognition of exceptional service/performance of the highest order", without distinction of race, occupation, position, or sex. Ref: mha.gov.in

The award was originally limited to achievements in the arts, literature, science, and public services, but the government expanded the criteria to include "any field of human endeavour" in December 2011. 

Recipients receive a Sanad (certificate) signed by the President and a peepal-leaf–shaped medallion. There is no monetary grant associated with the award.

On Social media, many people have claimed that since it is the prime minister who nominates the names and Pandit Jawahar Lal Nehru was the prime minister in 1955 when he received the award, it means he must have nominated himself.

On Twitter, you can see many posts with a similar claim.

Claim: Pandit Jawaharlal Nehru nominated himself for the Bharat Ratna

How names are selected for Bharat Ratna?

The recommendations for the Bharat Ratna are made by the Prime Minister to the President, with a maximum of three nominees being awarded per year.

This is the general practice but the official gazette notification of India which instituted the Bharat Ratna on January 2, 1954, doesn't mention anything about it. On January 15, 1955, another gazette notification was issued to allow the honour of Bharat Ratna to be awarded after the death of a person. Even this notification did not mention anything about the process.

In 1996, the then Supreme Court Chief Justice A.M. Ahmadi and other judges (Justice Kuldip Singh, Justice B.P. Jeevan, Justice N.P. Singh and Justice Saghir S. Ahmed) suggested to the Prime Minister that a committee be set up to lay down guidelines for selection of nominees. The judges suggested that the panel be headed by the Prime Minister, with the other members being the Lok Sabha Speaker and the Chief Justice of India or his nominee, and recipients be selected in consultation with the President. But successive governments at the Centre have not followed up on the suggestions.

In a separate six-page judgment, Justice Kuldip Singh too came down heavily on the absence of clear guidelines. "The procedure for selection of recipients is wholly vague and open to the whims and fancies of persons in authority

Ref: Outlook

Hence, the process under which the prime minister or the cabinet nominate names to the president is just a convention that is not followed strictly even till date.

Did Pandit Nehru nominate himself?

In an RTI reply in 2013, the government of India said that they don't have any record about who suggested the name of Pandit Nehru for the award in 1955. No records—letters, telegrams—between the former President and Prime Minister exist that hint at a suggestion made by the latter to the former regarding self-nomination for the award.

Then How did Pandit Nehru got the award?

In the summer of 1955, India’s first Prime Minister Pandit Jawaharlal Nehru flew over to the Soviet Union for a state visit. The trip, extending to almost a month, still remains the longest visit by an Indian Prime Minister to the region— which consists of Eastern Europe, Russia, and Central Asia.  The trip was a landmark visit because it escalated the Soviet-Indian friendship to a new high in that era of cold war-ridden bifurcation of the world order. 

When Pandit Nehru returned from the trip, the president Rajendra Prasad hosted a special state banquet on July 15, 1955, at Rashtrapati Bhavan. It was hosted to not just to welcome the Prime Minister from his foreign mission, but to nominate him for the highest civilian award of the land: The Bharat Ratna. In his speech at the banquet, President Rajendra Prasad said, "In doing so… for once, I may be said to be acting unconstitutionally, as I am taking this step on my own initiative and without any recommendation or advice from my Prime Minister; but I know that my action will be endorsed most enthusiastically."

Source: Dr. Rajendra Prasad: Correspondence and Selected Documents: Volume Seventeen, Valmiki Choudhary (ed.), Allied Publishers Limited, page: 456

Even the newspaper reports stated that the President himself confessed that he had acted unconstitutionally as he had decided to confer the honour “without any recommendation or advice from my Prime Minister” or the Cabinet”.

Conclusion:

Pandit Jawaharlal Nehru didn’t nominate himself for the Bharat Ratna, it was President Rajendra Prasad who took an unconstitutional initiative to confer the award on the Prime Minister.