After the first episode of “Chernobyl” aired on HBO in early May, “The Chernobyl Podcast” climbed to the No. 2 podcast across all categories on iTunes, shocking everyone involved. “I was like, wait a minute–this is Joe Rogan territory,” says showrunner Craig Mazin, referring to “The Joe Rogan Experience,” one of the most popular and long-running podcasts. To date, “The Chernobyl Podcast” has generated more than 10 million plays across various platforms, including HBO Go and HBO Now.