Alright kiddo, let's try to learn about how nuclear chain reactions work, but in a way that's super easy to understand.
First of all, imagine that you have a lot of tiny balls that are all stuck together. We call these balls atoms. An atom is made up of even smaller things, called protons and neutrons, that are all held together by something called strong forces.
Some of these atoms can be very special, like uranium or plutonium. These atoms are so big that they're not very stable or happy, so they'll eventually break apart into smaller atoms. When they do that, they give off a ton of energy in the form of heat and light.
Now, here's where things get really interesting. When one of these big atoms breaks apart, it can release even more energy than it started with. This extra energy can cause other atoms nearby to split apart too, and those atoms can also release more energy. This is why we call it a "chain reaction".
And the more atoms you have that can split apart, the bigger the chain reaction can get. This is why nuclear power plants use uranium or plutonium, because they have a ton of atoms that can split apart and cause a chain reaction.
Now, this can be very dangerous if we don't control it very carefully. If too many atoms split apart too quickly, then we can have a nuclear explosion that can cause a lot of damage. But if we control it just right, we can use the energy to power things like cities and cars.
So, that's the basic idea of how nuclear chain reactions work, kiddo. It's a little bit complicated, but I hope that helps you understand it better!