It's a Contax/Yashica (C/Y) mount. From the WY Cameras identification guide,
To identify them visually, it’s a similar situation to Minolta MD lenses – look for the position of the notch cut out of one of the bayonets. On C/Y lenses, it’s on the left of the bayonet.
Image of C/Y lens mount. From wycameras.com
Specifically, because of the D-shaped fixed pin next to the notched tab on the right, your lens appears to be made for Yashica bodies. I believe the position of this pin communicates maximum aperture of the lens to the camera body. Source: discussion at photrio.com
In order to adapt it to a Nikon F-mount body, because the C/Y mount registration distance (also known as flange focus distance) is shorter than the F-mount registration distance, you will need an adapter with a corrective lens in it. These types of adapters tend to reduce the image quality.