I got a job at the American branch of a Chinese company (Microsoft). It works for tier ones, not sure how you go about getting a tech job in a tier 3 city like Chengdu. You could probably teach English though, lots of opportunities still.
i'd imagine much the same process as working anywhere else abroad, you need to find work so that a company can sponsor a visa for you, to find a job start checking websites of target companies, there are a lot of multi-national companies here, if you speak/write mandarin chinese, that would be helpful.
Oh my... do not chose cities in the middle of nowhere in China. Only megacities there "work" for a Western person
Why?
Very hard for legal reasons: i.e. you go to a hotel, but they can't accept you because they have to blanks for police registration of foreigners, or PSB not being able to register your household simply because they have no computer system to do so, and there are no option for a foreigner to file for a residence registration on paper. Not to say, your Mandarin should be as good as that of locals, along the knowledge of local dialect if you venture far inland.
Unless you're fluent in chinese, it will be extremely difficult to get around in these tier 3 cities like chengdu. Shanghai and beijing are a bit more international, but even stilll, english is relatively scarely spoken. Just imagine having to go to the doctors', that would be extremely traumatic.