A man who admitted sexually assaulting four children over the course of nearly three decades in Cumberland County was sentenced Monday to eight years in state prison, authorities said. Andy Chanza, 67, of Newfield, pleaded guilty last year to four counts of sexual assault, according to a release from the Cumblerland County Prosecutor’s Office. Those charges originated from several incidents that happened in Vineland over a 29-year time period, the office said. Chanza sexually assaulted four children, who were all under the age of 13 during that time, investigators said. No other information wa…