Hmm... I suppose after the ACW we could have the USA break apart... in a TL of mine in which that happens, North America (USA, Canada, Mexico) breaks up into 23 nations, I think. After that, perhaps France becomes more powerful and defeats Prussia in 1866, so Germany never unifies... (we'd need to keep it from happening later, as well) Maybe somehow we prevent the unification of Italy, as well.
I'm not even close to an expert on Australian history, but couldn't we somehow prevent the commonwealth and have half a dozen or so Anglophone nations on the continent? Tasmania could become independant as well...
Let's see... well, I suppose the butterflies from my disunited Germany erases Karl Marx and the Communist Manifesto... but maybe that's for the better. Without Communism, stronger Nationalist ties could come about.
After Austria-Hungary breaks up (let's say it's defeated in a war with... oh, I dunno, France, in the early 20th century.), we could have the various South Slav states, instead of forming Yugoslavia, become independant from the start. Also, we could have more nations break away from Russia, such as Chechnya. (Are there any others?) I suppose we could also have a Basque homeland in there too. As for more European countries, what about an independant Scotland? (Maybe Wales? I don't know enough about them.) We could also let Denmark grant independance to Greenland.
In Asia, we could possibly still have Tibet and Manchuria as independant powers. Perhaps we can also prevent the union of Indonesia?
Well, I'm out of ideas, now. If we incorporated all of that into a TL, that's got to be around a hundred extra nations than OTL or so.