Since you're obviously more familiar with the direct military environment than I am, perhaps you can clear something else up, since my Google-fu isn't up to the task.
I pointed out -- sarcastically, I admit -- that firemen are EMTs because we don't have enough MD's to staff all the fire trucks, and because an EMT will do just fine at keeping you alive long enough to get you to the hospital where a real doctor can work on you. I similarly suggest that chaplains can do just fine at getting Private Jones to put down the pistol until the doc can arrive from the hospital.
The turtle pointed out that there are rules about what kind of things EMTs can do.
What are the rules about what chaplains can and can't do? You said "I would have an issue with [a chaplain] acting as a psychologist," but what are the regs and protocols regarding this issue? You're the battalion commander, and you think your chaplain is getting out of line and exceeding his training, his brief, and the demands of the situation. What are your options, and does the JAG have your back on this?