This is probably about a potential date in the fall of 1993, when Nirvana was one of the biggest bands in America. They played a show at William and Mary on November 7, 1993 - that's likely where they went instead of Duke.

Nirvana played the Cat's Cradle in October 1991, on a club tour that was booked before they unexpectedly became hugely popular. They wouldn't have been trying to book shows in basketball arenas before "Nevermind" came out.