He was Halayudha in Krishna lila. According to Premavilasa 24, Nityananda was a disciple of Ishvara Puri. Shri Jiva states that Nityananda was a disciple of Shankarshana Puri who was a disciple of Madhavendra Puri. But Bhaktiratnakara states that Nityananda took diksha from Laksmipati who was the guru of Madhavendra Puri. If this were the case then Nityananda would have been the great-guru of Lord Chaitanya and a friendly relationship could not have existed between the two. According to CBh. Madhavendra Puri dealt with Nityananda as a friend, while the latter showed guru-like reverence to the former.
Nityananda Prabhu was born on the thirteenth day of the bright fortnight of Magha (February-March) in the village of Ekachakra in the district of Birbhum in 1395 Saka (1473 AD). His father was Hadai Pandita (Hado Ojha) and his mother was Padmavati. His paternal grandfather, Sundaramalla Nakadi Baduri was a brahmana of the Radha clan.
Nityanda's past name was Kuvera and He was an avadhuta. Steven Rosen (Satyaraja das) says in his book Pancha-tattva, 3.13:
"Nityananda was considered an avadhuta sannyasi, although it is said that He never formally adopted sannyasa order. Avadhutas (the pure ones, in SB 4.29.11 p. called "most free") are usually associated with the Saivite tradition but there is a little known branch of Vaishnava sannyasis known as turiyatit-avadhuta. They are described in the Narada-parivrajaka-upanishad, Turiyatit- avadhuta-upanisad and the Brhad-avadhuta-upanishad."
In the same book (3.40) he lists twelve gopalas, associates of Shri Nityananda, with their identity in Chaitanya-lila:
Shridama (Ramadasa Abhirama of Khanakul-Krishnanagar in Hooghly)
Sudama (Sundarananda Thakura, brahmana ascetic)
Subala (Gauridasa Pandita)
Mahabala (Kamalakara Pipalai)
Subahu (Uddharana Datta)
Mahabahu (Mahesha Pandita)
Arjuna (Parameshvara Dasa)
Dama (Purushottama Nagara)
Labanga (Kala Krishnadasa)
Madhumangala, or Kusumasava (Shridhara)
Shri Nitai is Isha prakasha (CC 1.1.7-11), the cherished goal of Gaudiyas (CC 1.1.18-19), and is depicted as the trunk of the tree of bhakti (CC 1.9.21, 1.10.115)
His childhood sports up to twelve years of age are described in CBh. 1.9.12-99; His pilgrimage tours up to twenty years of ages in CBh. 1.9.100-136; His arrival in Navadwipa at the house of Nandana Acharya and his meeting Lord Chaitanya is described in CBh. 2.3.120-2.4.76.
Premavilasa narrates the following information relating to Nityananda Prabhu: marriage of Nityananda; settled life at Khardaha with Vasudha-Jahnava; death of seven sons soon after birth when Abhirama conveyed his humble obeisances to each; birth of Virachandra and Ganga later; both stayed alive and healthy despite Abhirama's offering of obeisances; hymns sung by Abhirama in praise of Ganga Devi.
Nityananda tattva: Mahasankarshana, Sesa, etc. (Gaura-ganoddesa-dipika 63-64). Sandhini-sakti; inward descent of Ananga manjari (Ananga manjari Samputika), in the form of Prakrti indirectly and in the form of Purusa directly. See Dharanishesha Sanvad in Brahmanda Purana of Vrindavana dasa Thakura, (2) Aishvaryamrtakavya and (3) Rasakalpasara tattva. Nityananda mantra: see Brahmanda Purana and Dhyanachandra Goswami's Paddhati (56-57).
Dhyana and Gayatri dealing with Nityananda: see Paddhati (as above) 50, 72. Nityananda Astaka composed by (1) Sarvabhaumma and (2) Vrindavana dasa Thakura; Nama dvadasaka on Nityananda composed by Sarvabhauma Bhattacharya; Astottarasatanama (108 names) of Nityananda (1) in Brahmanda Purana and (2) by Sarvabhauma.
The following are some primary works on Nityananda Prabhu:
Nityananda prabhu raisvaryamrtakavyam, Baranagar Pathavadi (Calcutta manuscript no. BA. copying date is 1260 BS (1853 AD). This Sanskrit text consisting of 128 shlokas is said to have been written by Vrindavana dasa Thakura. The ms. deals with descriptions of various aishvarya and madhurya-lilas of Nityananda Prabhu, as well as a note on His true nature (prakrti-svarupa). Another manuscript with similar contents titled Rasakalpasaratattva is also attributed to Vrindavana dasa and is available at Pathavadi collection ms. no. B 46.
Nityananda Vamsavistar, by Vrindavana dasa Thakura. The contents are as follows: Avatarahood of Virachandra; revelation of Virachandra; genealogy of Virachandra; Jahnava's pilgrimage to Vrindavana, in two parts – a total of six sections.
Nityananda Bhasya written by Ramrayaji, a disciple of Nityananda. It forms a commentary to Shikshashtaka.
He disappeared by merging with the body of Banka (Bankima) Raya Deity in Ekachakra grama – His appearance place.