When you register your child at the townhall right after he/she is born, you need to indicate the nationality of the child to be Chinese. So the birth card insured from the townhall will have this information on it. We got the Chinese passport for our child with such a birth card only. Or you can ask for GBA of your child. to be sure.
When the child has chinese passport, he/she is chinese, can not have Dutch nationality at the same time, But later, he/she surely can give up Chinese nationality and apply for Dutch passport. It is easy.