So i saw the daily challenges today and decided to help people get these done in about ten minutes. First put the difficulty on Heroic with thunderstorm on nightfall and run up to the first elite and wait for a checkpoint. Then you simply kill him and revert save until the challenge is complete. Afterwords run through the mission without any confrontation that's not needed a.k.a one particular shot and forklift glitch through the double doors when you are supposed to plant the bomb on the spire. If you don't know the glitch just google a quick runthrough on nightfall and all will be explained. Doing this should save time and effort. Have fun and good luck!!