From the official website of the Food and Drug Administration of the United States of America:
A recent social media video challenge encourages people to cook chicken in NyQuil (acetaminophen, dextromethorphan, and doxylamine) or another similar OTC cough and cold medication, presumably to eat.
The challenge sounds silly and unappetizing — and it is. But it could also be very unsafe. Boiling a medication can make it much more concentrated and change its properties in other ways. Even if you don't eat the chicken, inhaling the medication's vapors while cooking could cause high levels of the drugs to enter your body. It could also hurt your lungs. Put simply: Someone could take a dangerously high amount of the cough and cold medicine without even realizing it.
That's right, folks: if you want to get fucked up on chicken, stick with the beer can, not the cough meds. (And yes, that includes DayQuil, even though it doesn't have the sleep-inducing Doxylamine.)
Curiously, as Mediate notes, there doesn't actually seem to be much of anything searchable on TikTok or Twitter to suggest that is actually a thing the kids are doing these days.