Any advantage in GC processing if Spouse is Nepal citizen by birth on H4?

[jkb7]

Primary is on H1 - Indian citizen- EB2 priority date in 2016 (filed only for Primary by employer)
Dependent spouse on H4 - Nepal citizen by birth (not working)
Changed employer and filing GC again with new employer now. 
Questions are -

1. Can we get advantage in Green Card filing using wife’s Nepal citizenship (as for Nepal GC is current)?
2. If yes, what is the process for it? 
3. Also, at which stage we can add her in primary application ? —> during Labor/Perm or I140 stage?

[Attorney_17]

It is sometimes possible to use the spouse's country of birth through a process known as cross-chargeability. Since each case is unique, you are advised to discuss the specifics of your case with a knowledgeable US immigration attorney.