Eisenhower seemed to be under the impression that Nixon's fund scandal would sink the ticket, considering the Republicans were running on, in large part, an anti-corruption campaign. Of course, this didn't turn out to be the case, what with the Checkers Speech. But, even in the case Nixon rolls over and resigns right away, the Eisenhower ticket is still likely to win, albeit in a much closer race.
That does raise another interesting question. Due to Eisenhower's lukewarm response to the Checkers Speech, Nixon nearly resigned after the Checkers Speech under the belief that if an overwhelmingly popular public address wasn't good enough for Eisenhower, then he might as well take his ball and go home. The question is, what would be more damaging: the Vice Presidential nominee leaving the ticket in disgrace, or the Vice Presidential nominee seeing a massive upswing in support, only for him to be apparently forced out by the Presidential nominee anyway?