One unique example of chiasmus in the Book of Mormon is found in Helaman 6:7-13. In this example, the chiasm is not found in a discourse but in a historical summary.
A. And behold, there was peace in all the land,
B. insomuch that the Nephites did go into whatsoever part of the land they would, whether among the Nephites or the Lamanites. And it came to pass that the Lamanites did also go whithersoever they would, whether it were among the Lamanites or among the Nephites; and thus they did have free intercourse one with another, to buy and to sell, and to get gain, according to their desire.
C. And it came to pass that they became exceedingly rich, both the Lamanites and the Nephites;
D. and they did have an exceeding plenty of gold, and of silver, and of all manner of precious metals, both in the land south and in the land north.
E1. Now the land south
E2. was called Lehi,
E3. and the land north
E4. was called Mulek,
E5. which was after the son of Zedekiah;
E5. for the Lord
E4.did bring Mulek
E3. into the land north,
E2. and Lehi
E1. into the land south.
D. And behold, there was all manner of gold in both these lands, and of silver, and of precious ore of every kind; and there were also curious workmen, who did work all kinds of ore and did refine it;
C. and thus they did become rich.
B. They did raise grain in abundance, both in the north and in the south; and they did flourish exceedingly, both in the north and in the south. And they did multiply and wax exceedingly strong in the land. And they did raise many flocks and herds, yea, many fatlings. Behold their women did toil and spin, and did make all manner of cloth, of fine-twined linen and cloth of every kind, to clothe their nakedness.
A. And thus the sixty and fourth year did pass away in peace.
John W. Welch explains how this chiasm is more effective and obvious in Hebrew:
Just as divine names often appear at the center of biblical chiasms, at the very apex of this passage in Helaman 6, the words Zedekiah and Lord stand parallel to each other. The parallelism between these two names is intriguing not only because Zedekiah was the king and adoptive royal son of Yahweh, the Lord, but also because the Hebrew word for Lord (YHWH) constitutes the final syllable, or theophoric suffix, –yah, at the end of the name Zedekiah. Thus the central chiastic structure in Helaman 6:10 actually would have worked better and would have been more obvious in Hebrew (or its related Nephite dialect) than in the English translation. Joseph Smith would have had no way of consciously concocting this parallelism on his own.– Welch, “A Steady Stream of Significant Recognitions,” 347.
How did Joseph Smith create chiasmus like this which did not simply involved repeated words?