According to Chinese laws and regulations, locals will always have preference, and jobs available for foreigners (I am guessing you are one because you mentioned the question of what visa needed) will be those that locals can not perform because of technical knowledge or special skills required.

So, your only chance to land one to take care of children at home, would be for you to have some special skills or knowledge, like for example focus the application on teaching a foreign language to infants rather that changing diapers, feeding them and taking care of them.  Also, if you have knowledge of child psychology or experience in excellent techniques for raising children better, those will help support your application.  And of course, years of experience would also work.  Otherwise, it will be an uphill battle for you to land a job as aupier in China.

And the visa you will need is a "Z" work visa.  Good luck to you.