Bhai Nand Lal Ji was born at Ghazni, the son of a Persian secretary in Mughal service, and worked as a mirza and a tutor, at one point in the household of Prince Muazzam, later Bahadur Shah. He came to Anandpur and became one of the fifty-two poets of Guru Gobind Singh Ji's court.
He wrote in Persian, not Punjabi. The Divan-i-Goya, Zindaginama, Ganjnama and Tausif-o-Sana are his. His Persian is that of a court poet and his subject is the Guru.
Two short works in Punjabi are attributed to him, the Rehatnama and the Tankhahnama, which are among the earliest statements of the Khalsa code of conduct. Their attribution is debated.
His compositions are the only writings by a Sikh other than the Gurus, apart from Bhai Gurdas Ji's, that may be sung in a gurdwara.
A Persian-writing Muslim-educated court poet from Ghazni is not what most people picture when they picture the court at Anandpur, and he was one of its central figures.
He wrote in Persian, at a very high level, and his diwan and the Zindaginama are the principal Persian works of the Sikh tradition.
He had served in the Mughal administration at Multan before he came to Anandpur, and the Persian is the Persian of somebody trained in that world.
His work is recited in kirtan in translation and is read in the original by almost nobody. There is no complete critical edition in Punjabi.