Website doesn't seem to be updated, received email notification says:

"(...) We are pleased to announce the publication of Nim in Action. As a MEAP subscriber you can now download your copy of the finished PDF eBook. (...)".

And the final PDF is available for download.

Keep an eye out on Nim's website and Twitter for the print release.

Also, I am planning to create a dedicated page for the book. I'll likely submit it to HN right before the launch of the printed book.