I've been looking for solution with nested lists for several days. I've tried react-dnd, but when it comes to nesting - it becomes difficult to implement. So I've finally found sandbox with react-sortable and created this example:

https://codesandbox.io/s/sparkling-wave-krip2t?file=/src/styles.css

it works but that's hard to drag the item inside another item, because it doesn't has highlighting zone and you need just keep trying to drop it inside until it finally happens.

Maybe you can give me an advice how to implement this feature?