You can’t have a component nested in a component… Only instances.
If you try to make a component with a component in it, Figma will make put the first component outside the new component, and replace it with an instance.
Just right click the instance and “go to main component” to find it.
People commonly talk about “Nested components” but the right term is “Nested instances”
no, I didn’t “make a component with a component in it”
Table Cell is a component_set with 4 component in it, Figma make this kind of component look like instance, and it’s confusing.