Why are 2 one hour naps different than 1 two hour nap? Just do whatever you feel is best and at pickup just say she slept great! If mom wants details, let her know she would not sleep in the AM (you don't even need to attempt it if you know she will not sleep) but made up for it in the afternoon. And she is right, kids may need more sleep at daycare and you can tell her that's why you let her sleep the full naptime in the afternoon if she needs it. She sounds like the type of mom where you just smile and nod and then continue doing things your way.