Nephi concludes his discussion of the “future history” by proclaiming the victory of the Messiah over evil. All that men have done shall be revealed. Satan “shall have power over the hearts of the children of men no more.” It is interesting that in this context Nephi adds “for a long time.” Nephi is certainly aware of the final release of Satan from his binding for a short period at the end of the Millennium, but that is not his prime focus. He focuses on the binding, and the rest of the events at the beginning of the Millennium, but leaves unstated the full discussion of the nature of that time period. It is not the focus of his message, though he clearly understands more than he is saying.
Textual: Nephi formally closes this section with “and now, my beloved brethren, I make and end of my sayings.” This is an absolute termination of this discussion of Nephi’s prophecies, and is intended to close the concept begun with the citation of Isaiah.
From this point on to the end of the Book of Mormon, we have short and succinct chapters that form single units. Chapters 31, 32, and 33 are also chapters in the 1830 edition (following more closely the way Nephi would have divided his work). This closing phrase and the nature of the next three chapters suggests that at the end of this chapter Nephi has concluded his major work. The next two chapters are particular ideas - mini-sermons - that he has time to include. The final chapter is a very clear termination of the entire work.
We must assume that Nephi had other things to do than write a record (he was a king, after all) and that while writing this section he is of advanced years. It is therefore possible that this ending might have been conceived as a possible termination for his work. It is certainly a breaking point, where he left off writing for an indeterminable period of time.
In the life of Nephi the man, we should see this point as one where he stops from this task of recording the important knowledge he must leave for the future, and returning to other tasks. As he continues, he has time to enter some more writing, and will add two short sermons that are self-contained, and flow neither from the past text, nor from each other. They are simply things that he can write down, possibly in a single sitting.
When Nephi pens 2 Nephi 33, we must understand that he sees that his writing is at an end. It is tempting to suggest that this final testimony was written previous to our current chapters 31 and 32, but there is no evidence for that. The creation of the plates appears to have been part of what Nephi did (since the lack of room on the plates is the reason for no longer continuing to write at the end of Omni - Omni 1:30). There is never a mention of any attempt at creating new plates, so it would appear that Nephi created both the plates and the mode of binding them into a set. This bound set creates a logical ordering, supposing that plates were not easily moved from one section to another. With that physical form it would be surprising if 2 Nephi 33 were written before 31 and 33 because that would require moving plates within the set.