I think I figured out what I was doing wrong with the Nanite Health Monitor.

I recently submitted a bug report about the Nanite health monitor. I would hit the power on the medic kit, and it would cast a blue glowing effect around my character. In the description for the power, it reads that it is AoE and will effect up to 3 people. I would routinely cast it on people, but I would never know if people would have it unless, I cast it directly on them.

Last night, I noticed on several missions that I was able to cast powers and shoot at people without even having people targeted. So it got me thinking that, maybe the Nanite monitor works by casting it on to your self, and just standing next to people with it. I think that is how it is intended to affect the 3 people. I also think that if you cast it on a target who is not you, if they stand near another person it will affect the three closest people to them.

If that is how it works, then the long cool-down on the power makes some sense.

That is kinda how it works. But it does work the same way even if its cast on another player or friendly (like a Boff)

Whether you cast it on yourself or someone else - Nanite Health Monitor is an AOE heal that lasts for a set time on the person it has been casted on. During this time the power will automatically cast a heal on anyone within range of that character who falls below 75% of their health and is good for 3 heals as long as they happen within the buff time.

I believe that it is only the strength of the heal that is affected by the higher power ranks but I'm not 100% on that - someone else might be able to confirm.