Generally speaking, radiology program directors do not take a look at your application when they see you had a Nucs residency before. The exact opposite happens when an applicant has done IM or surgery residency in which case the radiology PDs really like these people.
There has been people who have found radiology residency after doing Nucs.
The only reason that you can give for doing radiology is that I don't have job, so I want to do radiology after my Nucs which many do not like it and see it as a negative point.
You may be able to find a spot in a program that has tough time finding a good applicant, if you are qualified enough though it is difficult.