That's one hardy bra Nami has to survive the fire completely intact like that. Do the manufacturers make armor as well? Cause I'm sure there's more than a few people out there who would be interested in a purchase.

It's made by the costume designers in Return of the Jedi.

It's made out of censortanium, sadly large quantities of it don't hold together for some reason.

Largest known quantity of it in the multiverse is in the Hulk's pants.

Incorrect. The largest known quantity is she-hulk's one piece swimsuit. The suit even canonically has the seal of the comics code authority according to at least one issue where she fought Stilt-Man.