A Chatham doctor is facing charges of sexual assault and uttering threats.Police say the suspect – whose name has not been released — was arrested Wednesday — after a nurse complained.  Authorities say the incident — which allegedly involved inappropriate touching – happened while the two were working at the Chatham campus of the Health Alliance.  The doctor is also accused of threatening a third party. Meanwhile the Health Alliance says it has been cooperating with the investigation. The doctor is not at the hospital until the investigation is complete.