Calcium supplements will help in the immediate short term. Make sure she has cuttlebone. You can feed her egg shells, if she'll eat them, for some calcium. Some pet stores will have calcium supplements for egg laying, check the ingredients to make sure it's simple and run it by your vet if you're unsure. Don't give any supplements in water--it might discourage her from drinking. Instead, sprinkle on her favorite fresh food or seed mix.
What are you doing with the eggs? If she isn't breaking them by like laying them off of a perch, which sometimes happens, please be sure to leave them in the cage. If she has eggs to sit on she's less likely to lay. That said, cockatiel clutches are fairly large I believe, so you may also want to buy some cockatiel sized fake eggs on Amazon to give her to sit on.
Regular hormone control advice absolutely also applies here. She needs 12+ hours of quiet darkness every single night to sleep. Take away any nesting locations (dark huts/covered nest boxes/etc). Don't touch her back or under her wings.
Finally, ask your vet about hormonal injections for her--idk where you live or whether it's approved in your country, but in the USA there's a drug going through clinical trials that's meant to decrease egg laying hormones. Lupron I think it's called?
