Based on the earliest textual sources, there are 66 occurrences of the past participle of the verb become. In most instances, the standard past-participial form become is found in the earliest sources (61 times), but in five cases we get the nonstandard became (which derives from the simple past-tense form). All five of these cases have been edited to become (as here in 1 Nephi 17:43). The critical text will, of course, maintain the original dialectal usage in these five cases. For further discussion, see under past participle in volume 3.
Summary: Maintain the few original cases of became as the past participle for the verb become.