Kanvar (Prince) Nau Nihal Singh was a Sikh ruler of Punjab. He born on 9 March 1821 and was the son of Maharani Chand Kaur and Maharaja Kharak Singh, himself the eldest son and heir of Maharaja Ranjit Singh Sher-e-Panjab and a grandson of Maharani Datar Kaur of the Nakai Misl. In April 1837 at the age of sixteen, he was married to Bibi Sahib Kaur, a daughter of Shaheed Sardar Sham Singh Attariwala (1790–1846) of the village of Attari in Amritsar district of Punjab.
After the death of Ranjit Singh, Kharak Singh became king but Kharak Singh soon became suspicious of his Vazir, a holdover from his father's court, Dhian Singh Dogra. He turned to his childhood mentor and friend Chet Singh who attempted to reduce the powers of the Dogra brothers. But Dogra rumors were spread, (an English sell-out mentioned) and soon Chet Singh was murdered. Kharak Singh was placed in 'haveli arrest' and slowly poisoned to death with (mercury) in his food. His son Prince Nau Nihal, on paper at least, ruled in his father's name but actually left the running of the government to the Dogras. He left Lahore.
Upon Kharak Singh's death, Nau Nihal Singh was in line to become Emperor. However, whilst he was passing through Roshnai Darwaza (the gate of the Hazuri Bagh at Lahore Fort) on returning from his father's cremation, masonry or stones falling from above, killing his companion and injuring the prince, who was taken into the fort by the Vizier Dhian Singh. Nobody else was allowed into the fort, not even his mother, who beat on the fort gates with her bare hands in a fever of anxiety. Two days later Dhian Singh Dogra announced that Maharaja Nau Nihal Singh had died from his injuries. Courtiers were shocked to see the body; his head was now severely crushed. The Dogra brothers, Gulab Singh and Dhian Singh are believed to have been behind the gate's sudden collapse.
Eyewitnesses described his initial injuries as being small blows to the head, he was able to walk. Nevertheless, he was pushed onto a Palki, which strangely was right at hand, by Dhian Sing Dogra who rushed the new Maharaja into the fort and had the doors to the ruler’s rooms locked. His family and courtiers were kept from him for 2 days. Later, when his mother and friends were allowed into the fort, Nau Nihal Singh was dead, his head having been smashed in, possibly with a rock.
Nau Nihal Singh died on 6 November 1840 at the age of 19 and his mother Maharani Chand Kaur became the Empress of Sikh Empire, from (1840–41) she challenged Sher Singh, the second son of Maharaja Ranjit Singh Sher-e-Panjab, the stepbrother of her husband Kharak Singh, on the grounds that her co-daughter Nau Nihal, Singh's widow, Sahib Kaur, was pregnant saying that she should assume regency on behalf of the unborn legal successor to her husband's throne.
In July 1841, Nau Nihal Singh's widow Sahib Kaur delivered a stillborn son. This ended whatever hopes Chand Kaur had of realizing her claims. But courtly intrigue had not ceased. Dhian Singh replaced the maidservants of the Dowager Maharani with hill women from his own country. The latter tried to kill her by poisoning her food and eventually finished her off on 11 June 1842, smashing her head with wooden pikes from the kitchen (some reports say they dropped a stone from a balcony crushing her skull.)