Assume that I do not want to do any post-processing, such as white balancing, etc. I would like to preserve the best resolution (for possible cropping). So the question is: Are there any quality differences between shooting in-camera JPG, versus converting NEF to JPEG using ViewNX, Picasa, etc.?
If you aren't interested in post-processing, then an in-camera jpeg will have the same resolution as a RAW image and the amount of detail in the image should be roughly the same. There is more flexibility in the RAW format in terms of post-processing and color corrections.
As an example, here is Digital Photography Review's review of the Nikon D800 showing the difference between high-quality jpeg and RAW -- http://www.dpreview.com/reviews/nikon-d800-d800e/22
There appears to be some confusion in terminology in your question.
NEF is the Nikon RAW standard and is superior to eg JPG if you do not wish to lose information.
ViewNX is a tool to view and convert NEF files to other standards - it is not an alternative to NEF but a way of working with NEF.
With respect to available information in the image, in camera JPG is inferior to NEF .
If you are as happy to use either NEF + ViewNX OR to use in camera JPG, then NEF is the superior choice. In camera JPG destroys information - retaining the NEF file means you have as much information available at a later date as it is possible to have.
Short answer: No. A Jpeg is a Jpeg however you arrive at it. It undergoes lossy compression, so it loses data. whether you do it in camera or through a software on a computer makes no difference theoretically. Having said that, some convertors have better engines than others. But that has nothing to with "resolution". This word is often misinterpreted. Anyway if it's quality you are after, the best advice would be to not use jpeg at all, except for uploading/sharing. Tif is a good format to to convert to from raw files, but there are many more.