Khuddaka Nikaya is a collection of Buddhist scriptures, kind of like a big book with lots of smaller books inside. Imagine it's like a toy box that has many different types of toys inside it.
This collection has 15 books or parts, and each one talks about a different thing. Some of the parts in this collection are stories, some are lessons, and some are even poems. You can think of it like having different colored blocks, balls, and dolls in your toy box.
These scriptures were written a long time ago by Buddhist teachers who wanted to spread the teachings of Buddha. They wrote them in a special language called Pali, which is different than the language most people use today. Just like how grown-ups may read books and tell stories to teach kids important lessons, these books were written to help people learn about the Buddhist way of life.
So in summary, Khuddaka Nikaya is like a big toy box filled with different kinds of toys, and each one teaches us something about Buddhism in a way that even a 5-year-old can understand.