“It’s not gonna be ‘Mamma Mia!,’ ” hinted Nikki Sixx of an upcoming Broadway show of his book, “The Heroin Diaries.” “We’re moving quickly [but are not] close to casting,” says the rocker, who’s celebrating his radio show “Sixx Sense” reaching 100 affiliates. On his band Mötley Crüe’s return to Las Vegas this fall, he says: “We’re not hanging it up yet. We want to go out on top.” But, “We’ve talked about a farewell tour that will come [with] an album and movie. We don’t want to be one of those bands who wear it out.”