O que significa "You ain't got nothing on me" ?

Hello guys,

So, I've heard the expression "You ain't got nothing on me" on a video and it got me wondering what the meaning of this sentence was. I heard it before in a Bruno Mars song, but in that case it was flipped to "I got nothing on you".

After a quick Google search I find out that, apparently, it means that someone is not comparable (or as good as) the person who says this expression (or the opposite, in the case of the Bruno Mars song).

Still, I'm not quite sure about the meaning of this phase and would like to hear what you guys have to say.

Thanks in advance