By Andrew Holleran Former NBA player turned social media star Rex Chapman is a part of NCAA Tournament coverage for Turner Sports this year. Chapman, these days best known for his viral Twitter account, made a tough mistake during the NCAA Tournament coverage for Turner Sports on Saturday. The former Kentucky Wildcats star made a big blunder when discussing Providence’s run to the Sweet 16. Chapman mentioned their former coach, Pete Gillen, claiming he was dead. “The first time since 25 years ago when Pete Gillen had God Shamgod — rest in peace, Pete Gillen,” Chapman said. Gillen, of course, i…