SPRINGFIELD, Mass. (WGGB/WSHM) – The 2016 murder conviction of Nickolas Lacrosse has been upheld by the Massachusetts Supreme Judicial Court. Lacrosse was found guilty of first-degree murder for the fatal stabbing of 17-year-old Kathryn Mauke at the family’s home in Springfield back in February of 2015. . Her ex-boyfriend, Lacrosse,…