I think it can be very easy for parents to see the resources and activities on offer at a nursery and not look further. Op, having seen how some nurseries self-promote, I'm not surprised you're worrying about your daughter missing out.
Take a step back from all the gleaming child-friendly furniture and think about what your daughter really needs. Is she happy with your nanny? Does she feel safe and secure? Are her needs (love, food, sleep) met? Does your nanny know your daughter well and is able to respond to her changing interests?
If your answer to all these questions is an unequivocal YES, then you have the best childcare in place for your daughter. Give yourself a shake, stick two fingers up at the gleaming nursery that won't know your daughter half so well as your nanny does, and carry on as you were, maybe suggest a class that you know she would enjoy.
If your daughter is obviously bored, unhappy or uncared for, that's when you look to change things.
Young children of this age don't really need structure and it's mainly in place for the staff's benefit rather than the children. Think crowd control 