Welcome to the forum. Unfortunately, the female will continue to lay eggs. Even if there isn’t a nesting box. Are you ready to take any hatchlings out of the nest if/when the cockatiels don’t feed them properly? This happens more often than people think. Female cockatiels can lay eggs at any time of the year. Your female will need a calcium supplement if she continues to lay. By leaving the nesting box in the cage, you are encouraging her to lay eggs. You could buy some dummy eggs, remove any eggs she lays and substitute them with the dummy eggs. This may stop her from laying for a while. It’s really important to stop/reduce her laying as she risks depleting her calcium levels which may result in her being egg bound or having soft shelled eggs which could break inside her when she tries to lay it.
Your cage is on the small side for 4 birds. Is there anyway for the budgies to have their own cage?

Do you have any pictures of your birds? We love pics here.