Neither science nor business are zero-sum games.
Let me be clear at the outset - what is occuring here has more to do with national prestige than with any real advantage to be gained.
Science: The free sharing of knowledge common to actual science (as opposed to proprietary business practice) is rising tide raising all of the boats docked. I for one welcome any and all progress China makes here, and think it will only accelerate developments in other labs as well.
Although free trade has been getting knocked about this (U.S.) election cycle, the globally interconnected economy has done wonders to the standards of living around the world. Despite forecasts of gloom, in America we have cars being manufactured by "foreign" companies, such as Honda and Toyota, and Dell has found it profitable to do some final assembly here as well. Even in the extremely unlikely event that China's investment in nanotech will only strengthen Chinese firms, the economic reality is that this would also end up benefiting other countries.
Don't believe me? Think historically - China has one of the strongest and fastest growing economies in the world, and their R&D funding is growing as well (though it lags far). But where was China 20 years ago? China is proof positive that countries can benefit profoundly by investments outside their own borders.