As they say, “there’s no business like show business,” and certainly few businesses have taken a bigger hit from the blackout caused by COVID-19 than nonprofit live theaters.As those theaters head into yet another uncertain season, many of them have upcoming fundraising campaigns and benefit events they had to cancel earlier this year.The League of Chicago Theaters had its event last weekend with “The Show Will Go On! A Youth Benefit Concert to Support Chicago Theatre.” The show had 60 local child professionals …