This seems to be a very worthwhile question and one that gets surprisingly little attention. If one looks at the track record of countries without strong capitalist traditions it is far from the norm to see businesses nationalized. From Brazil to Russia we see businesses fall under control of their governments, this is especially true of high profit operations that make use of natural resources. The argument may be made that the government is taking control of things that belong to the people themselves and that foriegn interests shouldn't profit from them, but one can see that it is more often just about the money.
Now if China were to move to nationalize it's economy one could expect severe world wide economic shocks, and more than likely the crashing of stock markets around the world. After all the current economic outlook centers around the rise of China, robust growth is not expected in the U.S., it is a tpped out market, new market share and profit growth of multi nationals has for some time come from emerging markets with China as the center of that. So why would China persue such a devastating action? First off there is the innate China centric view of the world, while China's growth has been fueled by opening up free market reforms there economy remains strongly controlled by the geovernment. Even where the government has takena hands off approach there is implied control, where what is happening is only happening because it is permitted by the communist party. Compare this to the U.S. where government control of the economy is fought tooth and nail, even where government intervention is warranted it is very hard to achieve. China has moved to control the supply of natural resources it gets from other countries, and China recognizes its regional and global power. It is just matter of time before China asserts it's perceived global pre emminence. Another thingthat could play into the move to nationalize foreign interests is the suspect ability of the U.S. to honor it's debts to China. If the U.S. cannot repay it's debt then seizure of it's private assets in China is a natural response.
So the world should temper it's expectations of how direct investment in China will pay out. The record on nations taking control of foriegn interests is not good, especially when one talks about a communist country that has a very strong view of it's place on the global stage. Make the investment to be sure, it is the best form of foreign aid we can make, and a poor China is more dangerous than a prosperous China, but be realistic about where that investment is leading.