Isaiah 9:6 (King James Bible) and his name shall be called Wonderful …
Here in 2 Nephi 19:6, Oliver Cowdery initially copied the text from 𝓞 into 𝓟 as “and his name shall be Wonderful”, but somewhat later he supralinearly inserted called after the verb be (the level of ink flow is weaker, but only moderately so). The original manuscript is not extant here but probably had the called (the reading of the King James Bible). The correction may have been made when proofing 𝓟 against 𝓞.
The King James Bible has examples of both “one’s name shall be X” and “one’s name shall be called X”, as in the following verse where both types are found:
The Book of Mormon also has examples of both types:
Thus either way of expressing a person’s name is possible in the Book of Mormon text. In modern English, speakers prefer the nonredundant “one’s name is X” rather than the biblically styled “one’s name is called X”. This preference was probably the reason why Oliver Cowdery initially skipped the called in 2 Nephi 19:6. The most reasonable assumption is that the original Book of Mormon passage read like the King James text (“and his name shall be called Wonderful”).
Summary: Maintain called in 2 Nephi 19:6, the reading of the corresponding King James text.