Vijaya,
First you need to extend the structure returned by the ABAP function module for this hierarchy (i.e. /NAKISA/OC_POSITION_STRUCTURE) to include this field. Then use the enhancement framework to ensure your new field is populated.
Now include the new field in the data element ("PositionHierarchyDataElement.xml").
At this point I would recommend a restart of the OrgChart application via the NetWeaver Administrator to clear the cache.
Then load the Nakisa AdminConsole and use it to add your new field into the list of fields to sort by and set to position 2.
Stephen