Dopedangel has the right of it. CC can launch a reader only if that reader is willing to be opened. By that I mean that to be supported a reader app must advertize that it can be opened by another program.
I jumped through the country-restriction hoops (they refuse to let it be downloaded to people in France), installed the nook app, and checked what it supports. Result: it advertizes nothing. There is no way that any program can tell the app to open a book.
We might be able to change CC to add the nook app to the list of readers if the app is installed. However, if we do this, then all that will happen is that the app will start exactly as if you started it yourself. It will not find the book you clicked on in CC. To be honest I can't see much use in doing the work as it saves 1 tap, but we will see.
Last edited by chaley; 01-22-2013 at 02:50 AM.
Reason: fix typo