Nishitha Sutra is a Jain Āgama text, and its name is usually understood as “the scripture of strict discipline” or “the text on prescribed conduct and expiation.”

A full line-by-line English translation depends on the exact manuscript/edition, because different Jain traditions preserve slightly different readings. So, here is the simple English meaning of its core teaching:

• It explains the rules of proper conduct for monks and nuns.
• It describes what actions are considered faults or violations.
• It teaches prāyaścitta — repentance, correction, and purification through discipline.
• Its purpose is to protect samyak chāritra and strengthen restraint, vigilance, and purity of life.

In simple English:

> The Nishitha Sutra teaches strict monastic discipline. It explains what is permitted and what is forbidden for ascetics, how faults should be confessed and corrected, and how one should live with complete care, restraint, and purity so that the spiritual path remains unbroken.

If you want, I can also give:

• a chapter-wise English summary, or
• a verse-by-verse translation of a specific part of the Nishitha Sutra.