The nucleus is perfectly spherical and thus not oriented. Even though it is not a point, but has finite dimensions, the charges are separated from each other and hence no overlap exists. Charge density at r = 0 remains unknown, but then the correction would also vanish, even it is different from zero.
There would be a small correction w.r.t. regular monopole term, if and only if there would exist some overlap. It doesn’t, so there won’t be any corrections.
Nature of correction-sources should be taken under consideration. There do remain dipole and Fermi contact contributions, which give rise to some corrections. I am looking forward to hearing the explanation during the seminar classes.