If I were you I would find out the two questions below, then retake the GRE.
1) Ask them about the average stats of accepted students (GRE, GPAs) rather than just looking at the base "requirements". Many schools
will tell you that requirements are 3.0 GPA and 300 GRE, but in reality the applicant pool is so competitive that unless an applicant has 3.5 GPA, 310 GRE, plus great everything else, he or she simply has little chance of getting in. Knowing how you stack up against past accepted students can help you make a more informed decision whether or not to apply.
2) If application deadline is right around the corner, ask them whether they would accept GRE if you retake and how long after the deadline you have to submit new scores. Then make a serious decision on whether to invest the time to study and retake GRE.
The best course of action is to study hard and retake the GRE if CRNA programs are competitive to get in. But if that's not a possibility at this time, it usually doesn't hurt to apply (unless the school doesn't look favorably upon re-applicants).