Like most Nightfalls, the Speed of Dark challenge is active. This requires you to beat the Nightfall with five minutes or more remaining on the clock. In order to meet this requirement, you’ll want to constantly be moving towards your goal, and trying extra hard to hit every one of the anomalies.
The next challenge, Unbroken requires you to beat the Nightfall with less than three deaths. For this challenge, use Momentum to your advantage and always keep moving. The extra health regen will go a long ways in keeping you alive longer.
Lastly, The Best Defense challenge requires you to shoot down at least 15 projectiles. Keep your eyes to the sky and this one should be fairly easy to complete.
Savathun’s Song gives guardians a decent 14 minutes to complete. As long as you are hitting as many anomalies as possible and keeping a good pace, you should be able to complete all of the challenges pretty smoothly.