When I was hired, my interview was a panel interview with 6 people, a mixture of supervisors and peers. However anywhere from 3 to 7 people can be included on the panel and it can be dependent on the job you are looking to apply for. I've also been included in interviewing new job candidates. Interview questions have always been situational and behavioral based, so really think about your past experiences both personally and professionally before heading in. Think along the lines of "What would you do if...", "How would you handle...", and "Do you think..." questions.
CHI's core values are Respect, Initiative, Compassion, and Excellence. Though it is not officially included, Teamwork is also highly valued. When they are interviewing, they aren't just looking for the candidate that is able to sufficiently do the work, they are also looking for someone who will fit in to the environment of the department with as much of a seamless transition as possible. They want someone with a personality that is going to mesh well with current employees as well as being able to perform the job duties outlined.