There are two types of nistha, nistha in relation to devotional practices themselves and nistha in relation to qualities that are favorable to the culture of such practices, such as humility, tolerance, compassion, respect for others, and so on. Generally the former follows the latter, although sometimes exceptions are seen and those who are steady in their practices appear to lack the some attendant favorable qualities.
In any case, nistha is about release from rajas and tamas. It is the influence of these lower mode that gives rise to laya, viksepa, etc.
Sattva comes with ruci, or ruci arises out of sattva as the lower modes’ influences subside in nistha and sattva predominates.
It is a question of rising out of the lower modes of nature in the context of sadhana-bhakti. Nistha is the top of the mountain. It is all down hill from there into the valley of prema. For those who have not attained it, the second sloka of Mahaprabhu’s Siksastakam should be contemplated. This verse explains the mood of chanting that will be helpful for overcoming anarthas. It is a mood of remorse for one’s condition with complete confidence in the efficacy of Krsna nama.
Nistha is the short term goal on the long and sometimes winding road homeward. From this point on, the road is straight but not narrow. It is broad and spacious, as rules become realizations and black and white turns to many shades of gray. This stage brings the heart of tender faith into harmony with the intellect. Thus one’s faith becomes well thought out, and more, because this exercise fosters intensified sadhana, it results in inner certainty, firm faith derived from knowing beyond thinking. Furthermore, this spiritual confidence is followed by ever-increasing humility, as the sadhaka is humbled by the depth of the subject being explored. He or she now knows that all are students forever in this field, a field of knowing in which the knowledge itself has its own agenda that includes us. Suddenly the subject—the self—begins to perceive itself as an object in the hands of Krsna nama, and the world viewed previously through the limitations of the mind expresses its own life backed by the will of God.
In nistha one does not see the world as the object of one’s enjoyment or exploitation. Humility arises and is synonymous with the absence of the enjoying spirit. Thus one can begin to see the world as it is with its own life in the service of God—everything moving in consonance with the will of God. This is the beginning of bringing the world to life—such a vision—by freeing it front he death trap of the mind that sees it only for one’s narrow minded mentally conceived purpose.
Nistha is characterized as that stage wherein the influence of rajas and tamas are almost completely destroyed—nasta prayesu abhadresu. This means that the fire of material existence has been extinguished but some smoke remains. But the remaining influence of these lower modes is not such that it can interfere with one’s practice.
As for how to attain absence of mental oscillation, the mind follows the heart. Thus one must chant from the heart with remorse for one’s lack of attraction/attention in consideration of how magnanimous Harinama is. Give your heart to Krsna nama and the mind will follow. One should shed tears over the fact that chanting does not bring tears to one’s eyes. This is much more effective than any mechanical technique.