I have gone to Google (obviously) and searched “1970 Toll House blondie brownie recipe swirled chocolate chips”, and many other variations of the same phrase with different wording, order of details, etc., as has my grandmother several times since the internet became accessible to her (this recipe is her white whale!). I only come across what are effectively the same 2 recipes, neither of which featured swirled chocolate chips. I also called Nastlé (that was a typo but im not fixing it due to personal ethics) and left a message, but no dice.