I'm assuming the nest box is empty right now? If not, remove the old nest which should be done anyway after the breeding season and put in your camera. I'm assuming it will be somewhere near the top of the nest box.
Then if a bird starts building a nest in there you should have no problems as long as you or anyone else does not go near the nest box and viewing what you see through the camera from afar.
Hi RP and a warm welcome to you from those of us on staff here at BirdForum