Once in the Book Editor, can you save a chapter? just curious, that may trigger the system to recognize a manuscript present.
I believe Editorial Reviews are completely optional and not required to publish.
I found the problem.
My books are comprised of all images, seperated by chapter. Nook requires at least one chapter with text, so I had to type in a line of text so I could preview the book.
The Manuscript editor is not intuitive at all. I'm expecting a complete button, or some other button to click when I'm done editing. Instead you have to go back to the Project page for the book to discover the Manuscript checkbox is now checked.
Quirky but I got the manuscript uploaded.