In modern English we tend to interpret might as a conditional modal that expresses possibility but not necessity (as in “he might do it”). Thus the use of might in 2 Nephi 2:26 tends to suggest that the redemption from the fall might be conditional, and consequently Joseph Smith replaced the might with may in his editing for the 1837 edition. In earlier English, might did not have the conditional sense that it does in modern-day English. And the Book of Mormon has numerous examples of such modal usage without any of the conditional implications. For a previous example, see 1 Nephi 3:19; for a complete discussion, see modal verbs in volume 3.
Summary: Restore the original use of the historically past-tense subjunctive might in 2 Nephi 2:26.