There are a few decent books on the subject.
Many blog posts and videos. But as for video tutorials of how to actually perform audio post production I think it is pretty limited. There are many video tutorials that deal with limited tips and tricks and there are a few basic ones (most for PT).
Gearslutz post forum will lead to to several books that will get you going. The now sleeping but still working site designingsound.org has lots of useful info and links.
Many sound designers have or had blogs (blogs seem to have gone slightly out of fashion these days so many are not that active). You will have to do some google-fu checking links from one page to another. Some will write extensively about a part of what we do but only once on a single blog and most other posts are more limited in scope etc etc.
To be honest I have seen there is a need for actual editing and mixing videos for Nuendo. I know of at least one other. He do mixer that have considered making some (as have I) but time is limited and the return of time spent is just not there.