In Jainism, "Nigod Nivaran" refers to the spiritual practice or austerity (tap) performed with the intention of liberating innumerable souls (nigod jeevas) from the lowest form of existence (nigod). The specific duration of the "Nigod Nivaran Tap" can vary based on tradition and local practice.

However, a commonly observed duration for Nigod Nivaran Tap among Jain lay followers (especially in the Shwetambar tradition) is 31 days. During these 31 days, practitioners engage in various forms of austerity, prayers, and rituals, dedicating the merit (punya) for the upliftment and liberation of nigod souls.

In summary:

Nigod Nivaran Tap is typically performed for 31 days.

If you are following a particular Jain sect or tradition, it is advisable to consult with a Jain monk or scholar for precise details, as practices might differ by community.