Go through this guide and follow step-by-step instructions to make a Chicken Nest.
The first thing you have to do is to dig one block of ground and add a bucket of water in it.
Then you need to cover the water with a spruce trap door and add an item frame at the top.
After this, you have to add an egg on the item frame and then use a horn coral fan on it. You have successfully made a chicken nest. The underground water will help the coral to stay alive.