The Nivo 1.1 distribution has an error and includes the old 1.0 js code in the min.'s file. Unfortunately, that's the file that is included with 1.3.2 of Responsive Lightbox.
You can fix this error by simply replacing the contents of the nivo-lightbox.min.js with the contents of the nivo-lightbox.js file which can be downloaded here:
https://github.com/gilbitron/Nivo-Lightbox/releases
Note that this new code fixes the bug where video would keep playing even after the lightbox was closed.