May I suggest the nurse might have considered it a good report because
a)there were clear margins which means they are confident they got all of the tumour;
b)there is no bone involvement which means tumour has not gone to a place that can be difficult to manage, and
c)the tumour is T1 which means it is early stage which gives your wife a reasonably good prognosis (certainly better than any other stage and better than some of the other sites of the oral cavity too).

As you say it looks like you are in pretty good shape (relatively speaking)