WE tried the idea below and it worked for a while.  If I left the spray (an aromatherapy sleep spray) and a torch on his bedside table he felt secure.  WE have also tried putting a dreamcatcher near his bed and even a little angel, but they didn't work for him.

We still struggle with it - all we can do, is minimise any harmful viewing/stories, have a lovely bedtime wind down, pray with him, leave his lamp on and leave the doors open so he can come to us in the night.  These help minimise his fear, but don't stop them altogether.

Can she remember the nightmares? If she can tell you what they are about would make it easier. For instance, if it's monsters, you can try a 'monster spray' or 'monster dust' ... use a bottle with water & glitter or a bottle of powder & label with 'monster dust' or spray & have her use it before getting into bed, telling her it will keep the monsters away.

If its not monsters, or you're not sure, you can still use this method but make something like a 'fairy spray' (or powder) with a label saying it will protect against anything.

A method such as this puts the idea in the child's mind that they are protected, so they go to sleep calmer, & often it stops the nightmares.