I don't know the exact meaning of heaven in this case, but you should take caution in thinking about 'Chinese religion'. It's not one religion, like Christianity or Islam. It's a group of traditional religions, not one unified religion. These religions are not unified in space (one tribe has slightly different views than the other), and not unified in time (traditional religions tend to change rather quickly, since they often depend on oral sources rather than written ones).

They are categorised as one 'traditional religion' though They are often categorised under one group as 'Chinese traditional religions', so their commonplaces are categorised and named. 'Heaven' may be one of those commonplaces, having different meanings in different traditions.