Hi Sheila,
It is important that the nest box is the correct size for a cockatiel. Since the male goes inside, it probably is. At 2 years old, she is only just old enough for breeding. For now I would throw away the eggs and take the box down. The eggs are no good since she isn’t sitting at night. Move things around in the cage to try to break the breeding cycle for now. If the pair is truly bonded, they will sit together, feed and groom each other, and mate. If this is not going on, then they are not bonded and may need more time to bond. But some birds do not bond with the mate that was chosen for them, and some bird do not make good breeders. Give them time to bond and let her rest from laying the eggs. If they start showing signs of a true bond and you have seen them mating, you can try the nest box again. If she still lays the eggs in the cage, move the eggs to the nest box and hopefully she will go inside to sit on them. Both parents take turns sitting on the eggs and the eggs must be kept warm around the clock or they will not develop. If she still fails to use the box or incubate the eggs correctly, the she probably isn’t going to e a good breeder.
Thank you for asking Lafeber,
Brenda