It's very easy. Just do this!

blaster1 is my childNode name.

Use:

• blaster1.zPosition -= 1.0 (if you want the parent Node to be on top of the child Node)

• blaster1.zPosition += 1.0 (if you want the parent Node under the child Node)

You have to do this because, by default the childNode is a part of the ParentNode and it inherits its zPosition.