Raja Nandivardhan was the elder brother of Bhagwan Mahavira in Jain tradition. After King Siddhartha’s death, Nandivardhan took over the family responsibilities and the household position. ( jainworld.jainworld.com)

In the Śvetāmbara tradition, when Bhagwan Mahavira wished to renounce worldly life, Nandivardhan, along with other family elders, requested him to remain for some time because of the sorrow in the family. Mahavira therefore stayed back for a while before taking diksha. ( jainqq.org)

So, the main known part of Raja Nandivardhan’s life in Jain literature is his role as Mahavira’s elder brother, family protector, and the person who helped delay Mahavira’s renunciation for a short time. ( jainqq.org)

If you want, I can also give this in Hindi or as a short story form.