Hi Jorge,
Thanks for using Syncfusion Products.
You can get the Nested Model selected row column indexes using GridDataChildTableModel selectionchanged event. This can be achieved in RecordExpanded event. From that you can get determinate row. We have prepared a model sample based on this. Please find it in the following location.
Please let us know if you have any queries.
Regards,
Deenadhayalan
NestedGrid_RowColumnIndex_cc4de594.zip