I was on a break from Days when Nancy was on previously. What issue did she have with Mike Horton?
Craig and Mike were both running for the Chief of Staff position at the hospital. Craig couldn't get the job based on his own merits so he and Nancy used Ali, a psycho nurse who was infatuated with Mike, to file a sexual harassment lawsuit against him when he rejected her (Mike and Carrie were hot and heavy around this time) and basically drag his name through the mud so he wouldn't get the job. It eventually escalated to Ali trying to kill Mike and then she tried to kill herself in the shower. She was eventually committed to the nuthouse.
I will never forget that scene when Claire walked in and found "M.I.K.E" written on Ali's bathtub wall in her own blood.