Just came across this little gem...
https://bookofmormonresearch.org/dark-skin

Are we to seriously believe that the color of one’s skin is the result of one’s moral behavior (2 Nephi 5:21)? Are we to believe that black people have a “dark and loathsome” skin because of their iniquity, whereas white people have a “fair and delightsome” skin because they are righteous? Skin color is determined by genetics, not by racist statements like this.

Samuel Lamanite Wall MormonThe same Book of Mormon writer, Nephi, noted that all people, “black and white, bond and free, male and female” are acceptable before God (2 Nephi 26:33), so the statements are clearly not racially motivated.

The Lord told Nephi that if his brothers rebelled they would “be cut off from the presence of the Lord” (1 Nephi 2:21). After the death of their father in the New World, Nephi and those who would follow him fled from Laman and Lemuel and their followers, which resulted in the older brothers being cut off from the Lord because they no longer had a prophet (Nephi) among them (2 Nephi 5:20). It is in the very next verse that Nephi speaks of the curse on his brothers, which the Lord brought about “that they might not be enticing unto my people” (2 Nephi 5:21). This means that the skin of blackness was imposed not as a curse, but so the righteous followers of Nephi should not mingle with the unrighteous followers of Laman.

Nephi’s brother Jacob chastised the Nephites, speaking to those “that are not pure in heart, that are filthy this day before God” and saying that the Lamanites “are not filthy like unto you” and that “the Lamanites your brethren, whom ye hate because of their filthiness and the cursing which hath come upon their skins, are more righteous than you” (Jacob 3:3, 5). From this, it is clear that sinfulness was independent of one’s skin color.

It is likely that the Lamanites intermarried with other pagan peoples in the New World, resulting in the dark skin. But when they were converted and began mingling with the Nephites, the result was that their skin became light again. It seems like a simple question of genetics. On the other hand, who are we to say that God, who is incapable of performing miracles wouldn’t do something like this?

For a detailed discussion of this subject, see John A. Tvedtnes, “The Charge of ‘Racism’ in the Book of Mormon,” FARMS Review 15/2 (2003). Originally presented as a paper to the 2003 FAIR conference, a slightly different version was posted on the FAIR web site and at http://www.blacklds.org/tvedtnes. A French version has been posted on the Idumea web site.
. That there were other peoples living in the New World alongside Lehi’s descendants has been demonstrated by John L. Sorenson, “When Lehi’s Party Arrived in the Land, Did They Find Others There?” Journal of Book of Mormon Studies 1/1 (1992) and Matthew Roper, “Nephi’s Neighbors: Book of Mormon Peoples and Pre-Columbian Populations,” FARMS Review 15/2 (2003).