What you want is not possible. But even if it would be possible it would not solve your problem. Because without the 2nd sortDescriptor the objects with hasRight==NO are still not sorted, and will be returned in a random fashion.
You need a third sortDescriptor, make that title
or creationDate
or any attribute that is unique to an object.
The objects with hasRight=YES won't be affected by the third sortDescriptor because the second sortDescriptor (sortOrder) is already unique for each object.
If you don't have another unique attribute you can use sortOrder
for hasRight=NO objects as well. Because your first sortDescriptor is hasRight all objects with hasRight=NO will still come later.
For example this is the resulting order if you sort by hasRight and sortOrder
hasRight | sortOrder
YES | 1
YES | 2
YES | 3
NO | 1
NO | 2
NO | 3