Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him)
What can we read to stop our children having nightmares?
You should teach them to read Ayat al-Kursi before they sleep if they are able to read it. If not, it should be read over them. If they are old enough, they should also read Ayat al-Kursi and Surat al-Inshirah after every prayer.