The plural usage in the conjunctive phrase “your teachers nor your ministers” appears to be fully intended, even though the surrounding text uses singular forms: “and also trusting no one ... except he be a man of God”. Joseph Smith replaced the plurals here with the expected singular forms teacher and minister in his editing for the 1837 edition. Earlier in this chapter, there is a similar kind of switching in number, from singular to plural and back to singular, although not within a single sentence as here in Mosiah 23:14:
Such switches in number are more common with pronouns, especially when used generically. Consider the following example from the original text where the singular an one was followed by the plural pronoun they:
Here is an extended example of multiple switching in pronominal number, also from the original text:
Thus the critical text will accept switches in number such as the one found in Mosiah 23:14 (“and also trusting no one to be your teachers nor your ministers except he be a man of God”).
Summary: Accept in Mosiah 23:14 the original switch in number from singular (“no one”) to plural (“your teachers nor your ministers”) and then back to singular (“except he be a man of God”); such number switching is fairly frequent in the original text.