Don, Topaz works great on NEX files or any digital files, really. I use Topaz Adjust, Detail, DeNoise, and Simplify, and love them all. I esp. like their presets and you can make your own. I rarely use any of the effects full-strength, though. If you have Photoshop, you can apply a preset in the Topaz plugin (and maybe tinker with Topaz slider bars first), and when you land back in PS with the "Topazed" image, go to Edit/Fade and consider fading/reducing the effect a little or a lot. Edit/Fade also gives you the option to change the blend mode, which can make a huge difference in outcome and give you many more choices. And you don't need layers to do this!
For example, say you want to get rid of color noise but don't want to add any blurring because you aren't worried about grain and you want to preserve details. You can select a standard DeNoise preset that removes all the color noise. It will also do some blurring (though DeNoise is very good about not going overboard on blurring). Back in PS, go to Edit/Fade, and from there choose the blend mode Color. You don't have to actually fade the effect (i.e., you can leave the percentage slider on 100% if desired), but just by changing the blend mode the color noise will be gone without any blurring because Color blend mode changes ONLY color. (I assume you can do the same thing by moving around the sliders in Topaz itself each time, but I find it easy to do with PS Edit/Fade because it's a tool I use a lot anyway. I haven't made my own DeNoise preset for this but perhaps should...)
My favorite blend modes for Topaz filters other than DeNoise are Multiply, Overlay, and Soft Light, and it's incredible how dramatically they can change the effect. The net result is as if you had many more Topaz effects to choose from -- enough to make your head explode, actually.
I don't know if you can do any of this in Lightroom unless you add the new layers software to Lightroom. In that case you would apply the Topaz effect as a layer, and if desired, reduce the intensity by lowering the opacity of the Topaz layer to less than 100%. You have access to the same blend modes using layers as you do in Edit/Fade. Or you can just leave blend mode on Normal, which is the default.
BTW you can use Edit/Fade on almost any action you take in PS, such as sharpening, brushing on color, cloning, etc. The key is to use it immediately after whatever step you want to change. And if you don't like it just back up in your History log and go back to before you used Edit/Fade.
Don't know what caused me to go off on a PS discussion, but I'm a big fan of Topaz plugins and that's how I use them! Others may very well have more efficient methods. I don't have any NIK filters at the moment, but I think all of the above would apply to NIK and any other filters.
BB, feel free to move this, of course!