You have already answered my first question, it is during the day.  Then you got my second, number and sex of the chickens though actual ages of the younger ones could help.  You are posting faster than I can type this morning but keep it up, it's good info.
I don't think it is a number of nests issue but that for some reason they are spending time in the nests.  I don't think it has anything to do with the size of the nests.  Until you know why they are spending time in the nest I can't tell you how to fix it.  Since it is during the day I'll speculate that some of your chickens are afraid of some others and are avoiding them.  The nests are a safe place for them to go. 
If it is pullets then they may be hiding from an amorous cockerel.  If it is a younger chick, they may be hiding from the hens or older adolescents.  During integration it is pretty common for my more immature ones to be where the older ones are not.  If they are all in the coop the younger are often on my roosts while the adults are on the coop floor.  Some may hide under the nests, they are pretty low.  If the adults are in the run, the young are in the coop.  The younger avoid the older. 
The same type of thing can happen with pullets trying to avoid an amorous cockerel.  They try to go where the cockerel is not and try to get somewhere that he cannot mate them.  Since you are building a new coop I'd guess they are fairly crowded. 
They may already be in the habit of using the nests as a safe place so ti it may be hard to break them.  The solution may be to give them other safe place they can go.  That may involve additional room or it may involve other places to hide.  That's not always easy to do, especially when you are busy with other commitments.  That may involve more run space, it may mean adding things things they can hide under, behind, or above in the coop or run.
It may involve locking up a chicken.  If the problem is an amorous cockerel locking him up can take care of the problem, the females no longer have a reason to hide.  If it is the chicks doing it because of age you may need to lock them up until they mature or you finish your new coop.  I'm speculating but I believe it boils down to not enough room or hiding spaces for a mixed age flock and/or cockerels/pullets going through puberty.  I don't think it has anything to do with number or size of the nests, just that they are safe places to hide.