Isaiah 5:1 (King James Bible) now will I sing to my well beloved a song of my beloved touching his vineyard my well beloved hath a vineyard in a very fruitful hill
In the printer’s manuscript for 2 Nephi 15:1, Oliver Cowdery initially wrote the first well beloved as beloved, perhaps under the influence of the immediately following “a song of my beloved”. In the Book of Mormon text, “my beloved” is much more frequent than “my well beloved” (note especially the highly frequent “my beloved brethren”); “my well beloved” occurs twice here in 2 Nephi 15:1 and once in Helaman 5:47 (“because of your faith in my Well Beloved”). Interestingly, Oliver also initially skipped the well in the Helaman passage (see the discussion for Helaman 5:47).
Thus Oliver Cowdery’s error is very natural; even so, he quickly caught his error here in 2 Nephi 15:1 and supralinearly inserted the well (there is no change in the level of ink flow). Of course, well beloved agrees with the reading of the King James Bible, and undoubtedly it agreed with the reading of 𝓞 (which is not extant here).
Summary: Maintain in 2 Nephi 15:1 the two occurrences of well beloved, the King James reading.