Ok, at the top of the board it says "Nobody owes nobody nothing"

This is a really complex idea. To break it down you have to start with the last part, "owes nobody nothing." In other words, "owes every single person at least something" because to owe "nobody" (or, zero people) "nothing," that would mean there is not a single person in existence to whom you would owe "nothing." Therefore, you would owe every single person at least something.

Then add the first "nobody," and the meaning of the complete phrase becomes "there are zero people in existence who owe every single person in existence at least something."

Which I disagree with. Whoever wrote that damn thing owes everyone an apology.