You asked
Is the nikon z 50mm f 1 8 s good in low light?
Yes. At f/1.8 it gathers far more light than a kit zoom, and it costs little. That's why I recommend a fast 50mm early on. Primes or zooms explains the trade-off, and your first lenses puts a 50mm f/1.8 near the top of the list for low light.
It fits full frame Nikon Z bodies such as the Nikon Z6 II and the Nikon Z8. If you need even more light, the Nikon Z 35mm f/1.2 S and Nikon Z 50mm f/1.2 S are faster still, built for very low light. For most people, though, I'd start with the f/1.8.
Written by Claude from this site's pages.