It seems that Nephi, and many of the ancient prophets, had a well-developed and sophisticated understanding of the mission of Christ, of his life, and also of his name. In the ancient world, the people greatly appreciated the importance of what we call "name theology." We do not have quite the same appreciation today. They had to know the name of the god that they were worshipping, and the name was usually very holy, kept sacred, and only spoken under certain conditions.
In verse 19, Nephi knew and used the Savior’s full name, Jesus Christ. Often, the Savior was referred to as the Only Begotten of the Father, the Father of Heaven and Earth, and the Son of God. There are a number of ways in which Nephi described the Messiah who was to come (see Figure 2). Possibly, the understanding of the Messiah’s name was something that came gradually and Nephi, Jacob, and all the subsequent Nephite prophets from this point forward knew him by his name, Jesus Christ.
Nephi had deep respect for and interest in the name of God. I am sure he emphasized this. So, when Nephi taught that "we talk of Christ, we rejoice in Christ, we preach of Christ, we prophesy of Christ, and we write according to our prophecies, that our children may know," this would have been a very solemn, spiritual, and holy teaching of his time.
Book of Mormon Central, "Why Must Christ’s True Church Be Called after His Name? (3 Nephi 27:8)," KnoWhy 482 (November 6, 2018).