Book of Mormon Central is doing a lot of great things. I completely agree that there were people in the promised land when Lehi's people landed, as this KnoWhy explains. So that's a good basis for consensus, IMO.
In my view, however, they landed in an area that was not occupied by a large number of people or any sort of civilization that could be considered a "nation." Lehi had told his family "And behold, it is wisdom that this land should be kept as yet from the knowledge of other nations; for behold, many nations would overrun the land, that there would be no place for an inheritance." (2 Nephi 1:8) Wherever Lehi landed, there would not be any other nations there. In my view, that means there would be unorganized hunter/gatherer people who were attracted to Lehi's society, technology, written language, etc. The people lived the law of Moses and were not absorbed into a larger, different culture.
The other aspect of the KnoWhy I like is the discussion of Isaiah. As I've written elsewhere, Isaiah mentions an "ensign" six times. The first four times, he is referring to the ensign for the nations to be lifted up on the mountains. (The last two times, in Chapters 30 and 31, are different connotations.)
Three of the four references to the latter-day ensign are quoted in 2 Nephi. As the KnoWhy indicates, Nephi was likening the scriptures to his own people, comparing the temple he built in the land of Nephi to the latter-day temple prophesied in Isaiah 2 (2 Nephi 12). (As a sidenote, it's cool there is a temple today in the same general area where I think the city of Nephi was anciently in Tennessee.)
Nephi may have been comparing Isaiah to his people in a generic sense; i.e., anywhere in the world where a temple is built, it could be compared to Isaiah 2. However, I think Nephi knew he was in the promised land prophesied by Isaiah as the location where the ensign would be lifted up to the nations of the world in the latter days.
I think he knew that partly because of Isaiah 18, which is the fourth reference in Isaiah to the ensign lifted up in the latter days. Nephi says he taught his people "all that which Isaiah hath spoken" but didn't write all of Isaiah's words. Although he didn't include Isaiah 18 in the small plates, that chapter is the one that explains the promised land was beyond the waters of Africa, which is how I think Nephi knew in which direction to sail from the Arabian peninsula. Following Isaiah 18, they sailed around Africa and across the Atlantic, landing in North America.
Here are the Isaiah references to the ensign.
Isaiah 5:26 (2 Nephi 15:26)
26 And he will lift up an ensign to the nations from far, and will hiss unto them from the end of the earth: and, behold, they shall come with speed swiftly:
Isaiah 11:10 (2 Nephi 21:10)
10 And in that day there shall be a root of Jesse, which shall stand for an ensign of the people; to it shall the Gentiles seek: and his rest shall be glorious.
Isaiah 11:12 (2 Nephi 21:12)
12 And he shall set up an ensign for the nations, and shall assemble the outcasts of Israel, and gather together the dispersed of Judah from the four corners of the earth.
3 All ye inhabitants of the world, and dwellers on the earth, see ye, when he lifteth up an ensign on the mountains; and when he bloweth a trumpet, hear ye.
17 One thousand shall flee at the rebuke of one; at the rebuke of five shall ye flee: till ye be left as a beacon upon the top of a mountain, and as an ensign on an hill.
9 And he shall pass over to his strong hold for fear, and his princes shall be afraid of the ensign, saith the Lord, whose fire is in Zion, and his furnace in Jerusalem.