When getting near the time of laying a female veiled will roam the cage restlessly looking for a site, be thirstier than normal, may not eat as much, etc.
Once the female starts digging you should not let her see you watching her dig. She will likely abandon the hole and if it happens often enough then it could lead to eggbinding. However, a veiled chameleon may dig more than one test hole before deciding on one. Once she has chosen a hole she may dig in it more than once and for several days. Eventually she should turn around bum down and lay the eggs. The laying can take several hours but sometimes it can be shorter.
Let her fill the hole in and go back up into the branches before you dig them up. Even if they are going to be infertile, IMHO, I would dig them up. I would want to make sure she laid them and I would also like to know how many she laid if she were mine.