I'm not sure you would be allowed to do a double major with Radiology and Nursing. Both programs are difficult to get into and both are difficult to complete. You generally have to go full-time. You should pick one of these majors.
Though the pre-reqs are probably very similar once you actually get into the core programs they are full time and require your full dedication and effort and I don't believe it would be wise to do both simultaneously nor do I believe you would be allowed to.