Comradeship // Freechat

You'll definitely want Chinese language ability. The good news is that Mandarin is not nearly as bad as some people make it out to be. There is a pretty steep initial learning curve as you get used to a tonal language, but it actually gets a lot easier (and more fun, imo) after that period. Grammar is extremely straightforward, especially for an English speaker.

Citizenship isn't incredibly easy, but neither is it totally impossible. China does not recognize dual citizenships, so you would need to renounce your existing citizenship. Assuming you are USian, that is a headache in itself (and will cost you a good chunk of money to do). Honestly this would be something that could come after the job. Get a job, move to China, eventually get permanent residency. You could move from PR to citizenship eventually, but that's going to be something that happens after you have lived in China a very long time. Permanent Residency will give you many of the benefits of citizenship. If you are married to a Chinese national, have relatives there, or can prove Chinese descent the process becomes a lot easier.

As far as the job prospects. Engineering is obviously a sought after position, but also a very competitive field. Your language ability and cultural knowledge will obviously never be as good as a native person in China, so you'd need to offer something that locals didn't already. Otherwise why would a company want to hire you instead of giving the job to a Chinese citizen. Like darkcalling mentioned, some kind of very specialized niche would be best.

There is also the possibility of working in an international company that might transfer you there, especially if you have language skills already. My company's regional head offices are there, and I have been angling for a transfer the past year or so as I brush up on my Chinese.