In Jainism, nigod refers to the lowest form of life, microscopic beings with only one sense (touch), living in clusters and experiencing extreme bondage of karmas. Nigod nivaran tap is an austerity or spiritual practice aimed at reducing the karmic influx and helping oneself and others (including nigods) move towards spiritual elevation.

While there is no widely prescribed austerity specifically named "nigod nivaran tap" in classical Jain scriptures, the spirit of this practice can be understood through the following Jain principles and practices:

1. Compassion (Karuna)

• Practice non-violence (ahimsa) in thought, word, and deed to avoid harming even the tiniest forms of life, including nigods.
• Be mindful of your actions to minimize the destruction of microorganisms.

2. Austerity (Tapas)

• Engage in external and internal austerities (bahya tap and antaranga tap) such as fasting (upvas), partial fasting (ekasana), meditation, and self-study.
• Dedicate the merit (punya) from your austerities for the upliftment of all souls, including nigods, by reciting prayers or intentions after your practice.

3. Prayers and Paryushana

• During Paryushana and other holy occasions, Jains often recite prayers like:

- "Mitti me savva bhuesu, veram majjha na kenai" (I seek forgiveness from all living beings, may I have no animosity toward anyone). - "Khamemi savva jive" (I forgive all beings).

• You can include a specific prayer or intention for the liberation or spiritual progress of nigod souls.

4. Knowledge Sharing (Gyan Daan)

• Spread knowledge of Jain teachings, as it is believed that knowledge can help elevate souls from lower to higher states of existence over infinite cycles.

5. Performing Lay Vyavahar (Charity)

• Give to causes that support non-violence, education, and prevention of harm to all living beings.

6. Special Practices

Some Jain communities observe special prayers or anushthans (spiritual observances) with the intention of "nigod nivaran":

• Reciting the Navkar Mantra or Navkarvalis multiple times with the intention of spiritual upliftment for all souls, including nigods.
• Participating in samayik (periods of meditation and equanimity) with a resolve for the benefit of all souls.

--- In summary: To practice nigod nivaran tap, engage sincerely in Jain austerities and spiritual practices, dedicate their merits for the benefit of all souls (including nigods), and live with utmost non-violence and compassion. Always couple your actions with the intention for the upliftment and liberation of all beings.

If you are looking for a specific ritual or recitation, it is best to consult with a knowledgeable Jain monk (sadhu/sadhvi) or learned layperson in your tradition, as practices may vary among Jain sects.