“Only Human” is the sixth mission in Crysis 3 and it contains four Nanosuit Upgrade Kits.
When you shut down a turret check out the room to the right. A nanosuit upgrade is located next to ammo creates.
Before you reach the point of the main objective where you should shut down the air defense Bravo, you will come across illuminated wall. Climb up to the floor with the lights on and follow the path until you reach the next nanosuit upgrade on the ammo crates next to a dead soldier.
During the mission you will get the secondary objective “Clear the Mines Around the Rebel ICV“. Next to the waypoint check out the smashed airplane and you will find a nanosuit upgrade kit.
The secondary objective “Scout out Downed VTOL” leads you to the waypoint and a crashed airplane with soldiers trapped inside. Remove boxes and crates to free the soldiers. inside the airplane you will find the last nanosuit upgrade in this mission.