Your Chinon mount lenses are probably Pentax K system. The Nikon has a deeper body. If you were to find or rig an adapter, the Chinon's lenses would only be useful close up. They would not focus to infinity.
Your options would be:
Use them for close ups. The zoom and the 50mm might be useful.
Buy a pentax digital body. The lenses would fit if they are K-mount, but would be manual focus, and meter in aperture priority or manual modes only.
Buy a Canon digital body and adapter.
Trade them in or sell on ebay to finance a dedicated lens.
Older Chinons were screw mount. They same goes, except that the Pentax digital body would also need a PS adapter.
As all are old third party lenses, and the 3rd party makers have lifted their game a lot in recent years, I think trading on even a third party dedicated lens is the way to go.
Cheers,
Wayne Lawler
http://ecopix.net