You could try to put a fake egg in the nest box and lock her in the coop for a few days to "retrain" her. I have found with my free range girls that if I remove all the eggs from a spot they go find another one. I like knowing where to find the eggs before I smell them (insanely hot summer here) so I just leave a fake egg where they like to lay outside and collect daily. 1/3 of my flock lays in nest boxes provided, 1/3 lays in the storage under the grill, and 1/3 lays under a bush between the house and a outside feed bin. I have tried retraining before but one would always find a spot to hide them so I gave in and allow them their spots. Since then they stick to them and haven't been hiding any more eggs from me and it's not a hunt for them anymore.