I've been terminated from a position

I have not been active on here for some time but I need some good advice. 3 years ago I was terminated from a nursing position. It was a very small hopital and there was a lot of bullying from management on down. I lasted a few months and I was suddenly called into the managers office and handed a list of complaints from my coworkers. I was completely surprised. I had repeatedly asked for feed back from both my coworkers and management and everyone said things where going great. I could think of nothing to say. I had been a nurse for several years at the time and never had a problem with my work or coworkers. I signed the paper in complete shock and left. Looking back I would have never signed the paper but whats done is done. My old manager welcomed me back with open arms no questions ask. Faat forward a few years and I took a job at another facility. They never asked about my other job when hiring me so no problem problems there, but the job is a horrible fit for me. I need to find another job soon. I know that the job that I was terminated from will come up in some of the interview. How would you all address this? Sorry for the long post but I need some advice.