Hi Gijs,
was this the documentation you were looking for?
https://apidocs.rnd.mendix.com/10/client/mx.data.html
If you're looking for specifically the documentation of Mendix 9, you can also check that: https://apidocs.rnd.mendix.com/9/client/mx.data.html, but you will notice that it hasn't changed much regarding this topic.
Note that you cannot call nanoflows by their name, as they are always used as input parameter to pass along the complete nanoflow object as argument.
Calling microflows can be done by name, but use with caution, as this may be deprecated in the future.
Good luck!