It's highly unlikely Cheney will win the GOP primary. But I can see her trying to play spoiler by running as an independent, or a third party candidate, especially if Trump gets nominated.
I will be violently ill soon for typing this, but better her than Trump.
Edit: just had a thought. Quite a few Dems in Wyoming switched party registration to vote for her. I wonder how much this tactic will spread. If Dems in states California, New York, Pennsylvania, Texas, Illinois and Florida switch party affiliations and vote for Cheney, they could seriously change the whole ballgame.