The nature of appearances is empty, that is correct. But then you have to ask the question: do appearances arise? They seem to , but do they? Do appearances remain, they seem to, but do they? Appearances seem to vanish. They seem to, but do they? When you understand that appearances do not arise, remain, or vanish, then you understand the emptiness of appearances. If appearances do not in reality arise, remain or vanish, how could their emptiness arise, remain or vanish?
How is this view different from nihilism?
Annihilationism is the assertion that something existent becomes non-existent.
To discover whether the view above is annihilationism, we have examine how appearances arise. First, if an appearance is an existent, can it arise from another existent? Or does it arise from a non-existent? As for the first, an existent does not arise from another existent because the arising of something existent is a contradiction in terms; and the arising of an existent from a non-existent is impossible. To address this, Nāḡrjuna writes:
An existent does not arise from an existent;
an existent does not arise from a non-existent;
a non-existent does arise from an existent;
a non-existent does not arise from a non-existent —
where then can there be an instance of arising?
If the arising of existents is not established, the arising of appearances is not established. If arising is not established, remaining is not established, and likewise, perishing is not established. If the three, arising, remaining and perishing, are not established, then there is no reason to accept the charge of annihilationism since I never suggested that there was an existent entity that could perish.
All we are left with is empty appearances: they are not real because no existence, etc., can be ascertained regarding them; they are not unreal since they appear. All we can say about them is that they arise in dependence.