You can use
Literals in the template
Code:
\MyBooks\PDF\{title}-{Authors}
The problem with this (PDF as a specific folder) is the simple template above, only works (as desired) for that format
You need another template for EPUB
(Those are simple samples. There is no Template, {format}, otherwise you could just stick {format} where I put PDF)
BTW does that Nook run Android?
Calibre Companion DOES allow per format filing