If I'm not mistaken, MAs and certainly PhDs are put in a different pool when considered work visas. And if she goes for academic jobs, it's virtually a guarantee for visa and a quick route to green card. There's always some risk, of course, but a PhD in CS has better chance than almost anyone else :-) Good luck!
If your field of expertise allows, I would recommend considering Australia & New Zealand.
Australia is not too immigrant friendly lately, but New Zealand will most likely give you a permanent residence if you have a well paying job, and you don't have a criminal record.