CHICAGO (AP) — A man accused of shooting an Alcohol, Tobacco, Firearms and Explosives agent on Chicago's South Side has pleaded not guilty.Ernesto Godinez is charged with assaulting an ATF agent with a deadly weapon in the May 4 shooting. He could be sentenced to up to 20 years in prison if convicted. The 28-year-old Godinez entered his plea during a brief hearing Tuesday before U.S. Magistrate Judge Jeffrey Gilbert.