nest

The home a bird builds for itself.

The home or bedding of some other animals.

Example: The mother wolf built a nest in her den before she had her cubs.

When an animal builds or stays in its nest, especially when taking care of its babies there.

If somethings is nested in something else, it is inside it. Usually, this is used for several things, with the second thing in the first thing, the third things in the second thing—for however many things are nested. This is often used in coding and computer programing.

Example: The computer program had nested for loops, that looked like this: