I am making a cheese and prosciutto stuffed chicken breast with an orange buerre blanc sauce ...the recipe has you make sauce and serve with

I looked up the recipe. The main reason you don't want to do that is that the sauce is too delicate. Also you are supposed to whisk butter in right at the end before serving. That kind of sauce isn't a bake-in sauce. The other problem is that the chicken won't brown properly if you bake it with a sauce over it.

You can't bake it in the sauce because it would break too easily.

Since their chicken breasts, cooking time isn't that long. After cooking, couldn't she remove the chicken pour off sauce, stir and place sauce on a platter with the chicken?

I would worry about the sauce breaking.

after you make the sauce, I think you could.