Over the years, journalist Sonia Nazario has resisted taking a public position on illegal immigration, the defining topic of her career. Lately, though, having exited daily journalism for book writing, she is “gingerly walking toward” sharing more of her own thoughts on the issue, she said. Madison audiences will get to delve into the topic with Nazario this week when she visits the city for several days as part of Go Big Read, UW-Madison?s common-reading program. Nazario?s 2006 book, “Enrique?s Journey,” is this year?s pick.