I guess it's okay to push back on the word "nationalization," as I don't think many people who are using it really imagine that the government is going to start running all the major banks for any length of time.
The FDIC is gobbling up 3 banks per week. The fundamental ways the "big banks" differ are their size and the degree of their political influence. I don't really see how size really matters, so that leaves influence.
If Geithner and the gang really think that putting these institutions in receivership is some sort hideous commie plot, they should call up the FDIC and tell it to stop doing just that.