So, you have melted nylon stuck to the inside of your boil pot? What is your pot made of (aluminum or stainless)?
I doubt powdered brew wash is going to help in this instance. You could try soaking in the strongest rubbing alcohol you can find. Let it soak for two days then try to scrub off. I doubt that will help either.
Besides that, i would get a copper scouring pad and try to scrape it off. If you have an aluminum pot, you will probably want to put an inch of water in the bottom of the pot and boil it for a half an hour once you are done scrubbing so that you can get a layer of oxidation back on the inside of your pot before your brew comes in contact with it.
Tap: Centennial IPA (SMASH)
Tap: Dogfish Head Ginger Saison
Bottle: Stone 11th Anniversary Black IPA clone
Secondary: Flemish Brown Sour Ale