Reddit mentions of Second Witness: Analytical and Contextual Commentary on the Book of Mormon, First Nephi: 1

They're a little pricey, but Brant Gardner's Second Witness series is awesome. It goes through the BOM one bit at a time and details all the latest scholarship on it.

>Second Witness: Analytical and Contextual Commentary of the Book of Mormon, takes a detailed, nearly verse-by-verse look at the Book of Mormon. It marshals the best of modern scholarship and new insights into a consistent picture of the Book of Mormon as a historical document created in and reflecting a particular place, time, and culture. It takes a faithful but scholarly approach to the text, reading it through the insights of linguistics, anthropology, and ethnohistory. The commentary approaches the text from a variety of perspectives: how it was created, how it relates to history and culture, and what religious insights it provides. It does not back away from the potentially controversial aspects of the text, providing answers to most but noting where other questions may remain unanswered. For the cultural and historical background, the commentary accepts the best modern scholarship, which focuses on a particular region of Mesoamerica as the most plausible location for the Book of Mormon setting. For the first time, that location--its peoples, cultures and historical trends--are used as the historical backdrop for reading the text. The historical background is not presented as proof, but rather as the explanatory context. While reading the text against a cultural background, the commentary does not forget Mormon's purpose in writing. It discusses the doctrinal and theological aspects of the text and highlights the way in which Mormon created it to meet his goal of "convincing . . . the Jew and gentile that Jesus is the Christ, the Eternal God."

Here's vol. 1, which just covers 1 Nephi:

https://www.amazon.com/Second-Witness-Analytical-Contextual-Commentary/dp/1589580419