You can call a microflow from a nanoflow but as far as I know it's not possible to call nanaflows from microflows
example of calling microflow in a nanoflow with a javascript action:
// BEGIN USER CODE
return new Promise(function (resolve, reject) {
mx.ui.action(microflowname,{
progress: "modal",
callback: function(result){
resolve("");
}
});
});
// END USER CODE