Nothing actually is
Everything. (using the word "is" just for simplicity)
It seems completely absurd at first, but that's the key, it solves both questions from OP.
I found it here where it is explained elegantly with logical arguments:
https://astezar.wordpress.com/nothing-is-everything/
They also give an intuitive example:
-Imagine a blank sheet of paper, there is nothing on it.
-Now draw a circle with a black pen, there is something on the sheet.
-Now put everything on the sheet,
paint it whole black with the ink, and show it to someone random in the street asking what they see. They will probably answer "Nothing, there is nothing on it" because there is no shape, it is blank black, empty. Everything is Nothing.
And, if I understand correctly, they say that as a result the Universe is Relative:
Something only exists relatively to what it is not
https://astezar.wordpress.com/relativity/
I mean I don't know, I was convinced by what they say but I'm happy to be shown otherwise