Assuming you are shooting raw (if not, start), and don't use NX, then go into the settings and change the sharpness all the way to max.
This will over-sharpen on the LCD, but will not affect the raw image, nor how Adobe (or I think any other than NX) view it.
Having done that, I find that I can much more quickly see if I have sharp focus as I zoom in, or at least see better exactly what part of the frame is sharp. In some ways it makes the images a bit ugly, but I find it a big help in evaluating focus in a quick look zoomed or not.
If using NX you can turn it back down, but I think it then defaults, which is why you might not want to set it up. And of course don't set it up for JPG.