Why are toddlers being sent to daycare when a nanny is there?

You could also cheat and choose an unemployed sim you want to be your babysitter, transfer them into your household when you leave, and transfer them back out after you get home. You could even create your own sim specifically for this purpose and give them all the traits that would make a good babysitter. Just make sure to give the babysitter a roommate so that their household remains in tact when you move them and you can transfer them in and out easily.