Christie probably won't be impeached, but a resignation as governor in order to run for president is a strong possibility, given that New Jersey's pay to play rules limit his fundraising for a presidential run if he's still the sitting governor of the state.
This is right. More dirt turning up against Christie makes it
more not less likely he'll be governor next year since it's probably more likely to cause him to abandon a run for president than lead to impeachment or indictment. But with both those as possibilities, Guadagno will probably be the next governor. Of course, she's being investigated herself presumably so who knows?