The name Nidra comes from the Sanskrit word निद्रा (nidrā), which means “sleep”. It is a learned borrowing from Sanskrit into Hindi, and a doublet of the word नीद (nīd), which also means “sleep”. The concept of nidra as a state of consciousness is mentioned in the Upanishads and the Mahabharata, while the goddess Nidra appears in the Devīmāhātmya. Nidra is also linked to meditation in Shaiva and Buddhist tantras and is used as a synonym for samadhi, the state of intense concentration, in some medieval hatha yoga texts. The modern form of yoga nidra, which is a technique of guided relaxation, was popularized by Satyananda Saraswati in 1976.
In the early Middle Ages the name was adopted by Norse raiders and settlers in Ireland in the form Njáll. The Norse transmitted it to England and Scotland, as well as bringing it back to Scandinavia. It was also in use among the Normans, who were of Scandinavian origin. A famous bearer of this name was American astronaut Neil Armstrong (1930-2012), the first person to walk on the moon.
One fictional bearer of this name is Kurisu Makise (牧瀬 紅莉栖) from the visual novel Steins;Gate.
This name is most likely influenced by the name Chris.
This is not the usual spelling in any of the Scandinavian languages (in Sweden and Denmark it is Freja and in Norway it is Frøja) but it is the common spelling of the goddess's name in English. In the 2000s it became popular in Britain.
Usage of this name is, most likely, influenced by the name Aisha.