Nikon 's best portrait lenses have excellent bokeh, and the appropriate lengths to prevent excessive distortion of facial and body features, meaning--no wide-angles make the grade,and no classic normal lenses make the grade either. Nikon's commonly accepted "best portrait lenses" are typically considered to be the 85mm 1.4 AF-D, the 105mm f/2 AF-D Defocus Control, the 135 f/2 AF-D Defocus control, the 70-200 f/2.8 VR (the original version,since the new one has yet to truly earn its rep), and the 200mm f/2 AF-S VR-G. Those five are probably Nikon's best portraiture lenses. Those are the best, then there are "the rest".
Some of "the rest" are older lenses like the old 85mm 1.8 H-series, which is long out of production, but will work unmodified (it is a pre-AI lens from the 1960's) on a baby Nikon like a D40, D60,D3000, or D5000. The old 70-150mm f/3.5 Series E is actually a pretty decent lens for portraiture, with a very useful focal length range and an affordable price.