The text here has the second person pronoun form you with the imperative choose. Historically, you is the object form for the pronoun ye. But elsewhere the Book of Mormon text has choose ye, not choose you:
The usage here in Mosiah 29:25 agrees with the King James Bible usage (which consistently has choose you):
Notice that the example from Alma 30:8 cites Joshua 24:15, yet the Book of Mormon has ye instead of the you of the King James Bible.
David Calabro points out (personal communication) that the King James Bible consistently has you rather than ye because in the Hebrew the expression “choose you” literally reads “choose for you”, thus the objective pronoun form you is appropriate as the indirect object in the English translation. But the Book of Mormon text seems to treat the ye and you as the expressed second person subject for the imperative choose, thus allowing either ye or you. For some discussion regarding the variation between ye and you as the subject pronoun form, see under 2 Nephi 7:1; for a complete discussion, see under YE in volume 3. There is clearly no strong evidence within the Book of Mormon text to emend you to ye in Mosiah 29:25 or the opposite in Alma 30:8 and Ether 6:24. In each case we will follow the earliest textual sources in determining whether the second person pronoun form in commands should be ye or you.
Summary: Retain in Mosiah 29:25 the second person pronoun form you in “choose you by the voice of this people judges”, the reading of all the (extant) textual sources; elsewhere the Book of Mormon has two examples of “choose ye” rather than the biblically styled “choose you”.