Grant Hardy discusses the presence of Second Isaiah in the Book of Mormon.
Grant Hardy, The Annotated Book of Mormon (Oxford: Oxford University Press, 2023), 67
Nephi copies these chapters from the Brass Plates, though most scholars believe that Isaiah 40-55 (Second Isaiah) was written in the mid-6th c. BCE, a generation after Lehi’s family had left Jerusalem. Believers might respond to this discrepancy by positing a divinely sanctioned updating of Nephi’s writings, or a very free translation. In any event, there are similar problems for all the extended quotations from the Hebrew Bible, including the chapters from First Isaiah reproduced in 2 Ne 12-24. The BoM follows the King James Bible quite closely, even though the underlying Hebrew text of that 1611 translation—the Masoretic Text (MT)—was the end result of a process of writing, editing, revising, augmenting, and merging sources that continued for many centuries after 600 BCE. In this edition, many of the BoM modifications to lengthy quotations from the KJV are bolded, to show places where the BoM might function as biblical commentary of sorts. As with other such quotations, many of the changes in chs. 20-21 are to words that were italicized in the KJV (indicating that they were added by the translators when the Hebrew original yielded incomplete sentences in English). Additions of conjunctions, interjections, and minor clarifications are also common, as are transposed words. From the perspective of the narrative, it is unclear whether these changes to the KJV are supposed to be restored original readings, or Nephi’s own glosses on Isaiah intended to “liken” scripture to his family’s current situation. In any case ,the deletions, additions, and substitutions of a few words here and there are reminiscent of how 1 Chr 16.8-36 adapts Pss 105, 96, and 106 to fit a particular historical context.