Isaiah 13:21–22 (King James Bible) but wild beasts of the desert shall lie there … and the wild beasts of the islands shall cry in their desolate houses
Here we have two cases where there has been a minor change in the number of a noun. In the first case, the singular desert was accidentally replaced by the plural deserts in the 1906 LDS largeprint edition. In the second case, the plural islands was replaced by the singular island in the 1874 RLDS edition (and subsequently followed by the 1892 RLDS edition). Later editions have not followed these two typos. In both cases, the number in the original Book of Mormon text agrees with the King James reading.
It is interesting to note that in Isaiah 34:14 (which is not quoted in the Book of Mormon), both of these references to wild beasts are repeated:
Although the singular island is found in Isaiah 34:14, it is very doubtful that the 1874 RLDS change from islands to island would have been based on that passage.
Summary: Maintain the singular desert in 2 Nephi 23:21 and the plural islands in 2 Nephi 23:22; in each case, the earliest Book of Mormon reading is the same as the King James reading.