Can karma be destroyed by other Niyamas? Can karma be destroyed by other Niyamas?

Can the other four niyamas from the "Five Niyamas" remove a person's karma? Or just affect it?
No, if speaking of "can one deed make another undone" (MN 101), Breath, but by the deed of traing the mind, one can reach the ability to bear results of fruits from deeds easier. See the The Salt Crystal.

Since it has much impact of general ways of thinking, living mostly in a world of believe that unrightouseness could be corrected, the Essay Wisdom over Justice might give certain inspiration, dealing at least with this issue outwardly.

For Suttas (teachings) on kamma (actions) look up here: Kamma

In detail, of what certain sects see as skillful (here Niyamas), there are certainly deeds which are not benefical at all for even lighten effects of old kamma, not to speak of going beyound. But such would need the discussiin of each of this practices. Some of this classical are benefical, kusala-kamma.

To get rid of the effects of ones previous deeds eternally, there is just one refuge: Nibbana.

[Note: This is a gift of Dhamma, not meant for commercial purposes or other low wordily gains by means of trade and exchange]