One thing we always used to tell mothers about to approach the big milestone of the nursery, is that the settling period is not only for your child but also for yourself! Most parents who have their kids already settled will tell you how much they love it and how it is more difficult to go home from nursery then the opposite. But this will happen with some time and adjustment.
One very important thing to do at the beginning is to trasmit trust to your baby, to the keyworker and to the environment in general. Your child knows you more than anything, and will sense your feelings. Even if it feels really hard, do your best to show how much you believe in this choice, and see the bigger picture. Other very useful tricks are in the post here.
Remember: there is never a one-size-fits-all solution, every child is different and so you are. Approach the settling and the first period in collaboration with manager, keyworkers and the family. Soon your kid will cheerfully wave you good-bye, and you will know that they will have a great time.