To answer that question, we must ask another one first: What kind of nightscape will you be shooting? For brevity, I’m going to focus on the most basic nightscape, a single exposure. Stacked images, panoramic, and long-focal-length nightscapes involve another level of technical complexity around topics like image registration, masking, nodal points, parallax, stitching, and tracking hardware. It would take quite a few more pages to cover them all adequately.
Earlier, I talked about the trade-offs in nightscapes between image quality and light gathering. When deciding on your camera settings, this is where the rubber meets the road. If you want lower noise (less grainy images), use a lower ISO value. Unfortunately, this comes at the expense of light gathering.
If you want better details, especially sharper stars at the edges of your images (less coma), close down your lens a few f-stops from wide open. But again, this comes at the expense of light gathering. Likewise, if you want more pinpoint stars across your entire field of view, you must shorten your shutter speed.