In this chapter, Solomon meets the queen of Sheba and after other events his life is concluded.
This chapter copies a significant amount of material from 1 Kings 10, which has two main sections. It first tells us the story of Solomon's meeting with the queen of Sheba, and then it tells us about Solomon's great wealth and power. This chapter also concludes with a brief account of Solomon's death, which is taken from 1 Kings 11:41-43.
The first question I find myself asking about this chapter is, how does it fit with the larger themes and narrative in Chronicles? To me, this chapter feels similar to 2 Samuel 21-24, which were a sort of appendix with miscellaneous stories from David's life. I feel like these are a handful of miscellaneous stories from Solomon's life that don't really play much into the larger narrative of Chronicles like the temple project.
I think to some extent, this chapter could be seen as glorification of Solomon (which is another one of the themes of Chronicles), and perhaps it can be seen as a depiction of God's blessing over Solomon in response to Solomon's devotion to God in the previous chapter. Since the Chronicler is certainly trying to emphasize the connection between faithfulness to God and material blessing (consistent with Deuteronomy), perhaps we could see Solomon's wisdom and his blessing as a fulfillment of the promise that God made to "establish" him. But like I said, I feel like this is a fairly weak association and I mostly think these are stories about Solomon that just don't fit anywhere else so we get them here at the end.
The next question we should ask is what differences exist between the narrative in Chronicles and the same stories from 1 Kings? The answer is, very few. Some of the numbers are different but the vast majority of the text is the same. There is one important difference which is that Chronicles leaves out the entirety of 1 Kings 11:1-40. This is a major change, because that part of Kings is extremely critical of Solomon. In it, we are told that Solomon had many foreign wives, which was forbidden by the Law (and Kings paraphrases from Exodus 34:12-16 which essentially forbids foreign wives). Then we are told that because Solomon was led on to worship other gods by his wives, the LORD raised up enemies to fight against Solomon and would "tear the kingdom from you" (1 Kings 11:11). It's a long and harshly critical section and Chronicles omits it entirely. This is definitely part of Chronicles long-standing pattern of idealizing Solomon (as well as David).
Other than that, I think the main theme of this chapter is just to show us how amazing is Solomon's kingdom. There is a particular emphasis on exotic luxury items. We can also see that much of Solomon's wealth was based on long distance trading in partnership with Hiram, and the queen of Sheba herself appears to have arrived as part of a substantial trading expedition. Some of the different elements mentioned: the fine spices and precious stones (v. 9), gold, exotic wood (almugwood, v. 10), ivory, apes and baboons (v. 21), the chariots imported from Egypt (v. 28) and many other things.
As I said elsewhere, this is the apex of Israel's power and wealth in the bible. David defeated all of their national enemies and now Solomon is reaping the benefits, using the slave labor as well as the peace to build the temple and many other structures and monuments, and he is financing it all through long distance, international trade, as well as accruing luxury goods. All of this enhances Solomon's prestige and we see that in the queen's response when she is overwhelmed at all of Solomon's amazing stuff. Since Chronicles leaves out all the negative stuff about Solomon, we are left with an entirely positive picture of his reign.
In the next chapter, we will nonetheless see Israel fracture into two nations, the northern kingdom and the southern kingdom. The rest of Chronicles will be entirely devoted to the history of the southern kingdom, Judah.