This achievement is obtained in Operation B Misssion 3.
The trick is here to kill the Jackals (enemies with pink shields) before their shield regenerate. When you attack them it will take down their shield so you can kill them. The best way to do this is to avoid them as much as possible. First go south and let you fellow Spartans die to the turret. They tend to take down enemy shields and not finish them off. Then from there focus on killing the elites and healing with the armor ability when needed.
You can use the Cloak ability which can be picked up right at the start of the mission or purchase the Overshield before the mission if you prefer a different option.
This was recorded on the Xbox One version of the game but the achievement is completed in the same way.