The nose isn't something that you should expect to change with HRT, however that doesn't mean that it won't change. I have read about many people saying that their nose changed. After all, your nose is not all bone, and the way I see it, cartillage can change. Even bones seem to change a little in patients in their thirties, from my readings and experience (my hips are actually widening by the looks of it).
So don't be 100 % sure that your nose won't change at all. And even if it doesn't, changes in the rest of your face could very well make it look much better. It actually happens often.
So, yeah, I would wait if I were you. Plus, if you get it done with an eventual more extensive FFS, I'm guessing that it will be easier for the surgeon to make it look harmonious that way.