Once more, we have an error by the 1841 typesetter. In this case, his eye skipped from the first to the second in in this passage, thus ending up with the abbreviated expression plus an odd use of the semicolon: “and all manner of miracles did they work among the children of men; and in the name of Jesus”. The subsequent LDS edition (1849) restored the missing text, “nothing did they work miracles save it were in”. The copytext for the 1841 British edition was the 1837 edition. For this part of the text, the first in occurs at the end of the line, the second just below, one word from the end of the line, thus facilitating the skip:
Summary: Maintain the longer, original text in 4 Nephi 1:5, “and in nothing did they work miracles save it were in the name of Jesus”.