I'm pretty excited, so I just wanted to share. I soloed the weekly heroic, and seeing how doable that was, I decided to solo the nightfall and it worked. I know I can't solo all the nightfalls, but this one is doable, so give it a shot! (I used my lvl29 hunter.) I have discovered one way to take out the lieutenant in the tank that I had not seen yet, so I wanted to share. First, kill off some of his minions, they are just annoying. Then get the tank to move to the left half of that clearing. Then, without being seen by the tank, climb onto the ledge on the right, and move forward slowly until you can just see one of his thrusters showing. The way that big central rock is shaped, you should be able to get it so that you can see his thruster and the top part of the tank is covered by overhanging rock. Now get out your trusty Ice Breaker, or other favorite distance weapon of choice, and begin shooting the little bit that is exposed. He will not move; he will just continue to shoot rockets into the rock overhang. It takes a while, but it works.