The 1837 edition omitted the fronted direct object, the pronoun this. This obvious typo, however, was maintained in the 1841 British edition, which was set without any editing from the 1837 edition. The 1840 edition restored the correct reading, as did the 1849 LDS edition (the latter by reference to the 1830 or the 1840 edition). The earliest textual sources (𝓟 and the 1830 edition) support the occurrence of this here, as does usage elsewhere in the text. Nearby, Oliver Cowdery initially omitted such a this in his copywork:
Summary: Maintain the direct object this in 3 Nephi 11:15 (as well as in 3 Nephi 4:25).