If Hillary really adopts a strong anti-immigation policy, arguing that illegals drive down wages for average working Americans and hurt social services for "the children" (which is quite true and something I could definitely see her doing), and the Pubs run a business as usual candidate, she will win big in many red states with big illegal populations like AZ, NV, NC, etc.
"Hillary Rodham Clinton... For a Stronger, Middle Class America"
She can work off John Edward's "two Americas" theme, and argue that illegals are hurting the middle class, and benefitting the businesses and wealthy people that employ them. And there's some truth there. Look at how the middle class has been driven out of southern California, as illegals have pressured wages for the average person, and housing prices/quality of life in working/middle-class neighborhoods.
It's a powerful "you v. the elite" message. She can run against the elite that favors cheap labor and political correctness.
And that's not even getting into the national security arguments for border security.
We need a nominee who is on the right side of this issue, as she will trample right over a RINO with no conservative principles.