If you sent him to the Ottoman Empire as an adviser (which at one point he requested), then you could see Nappy train Ottoman troops. I'm not thinking big, Napoleon led campaigns which massively enlarge the Ottoman Empire, but rather French-trained, Napoleon led Ottoman troops who the Sultan can use to crush the Janissaries. If you can do that, while the European powers are fixated on the French Revolutionary Wars, then the Ottomans will be in much better shape coming into the 19th century.
This would end up creating some small, but very interesting ripples that could lead to a much better run Ottoman Empire that is much more capable of both modernizing and fending off European imperialists. The first thought I had is that with this new French-trained army the Ottomans could re-establish control over Egypt.
So the Ottomans get a new generation of officers, who are trained by Napoleon and cut their teeth on military campaigns with him, first in Constantinople as they toppled the corrupt Janissaries, then in Egypt, where they re-established the power of the Sultan. This would be a forward looking, modern corps of officers (the Young Ottomans come early as it were). Maybe Muhammad Ali (of Egypt) ends up as one of these officers, and pursues an Empire-wide modernization program.
The link with France that Napoleon establishes ends up sending many more Ottoman officers west for their education, pushing the progressive attitudes of these officers.