During the Crysis 3 Mission 2: Welcome to the Jungle, you can collect three Nanosuit Upgrade Kits.
Nano Upgrade Kit no.
At the beginning of the mission, Psycho will show you where to collect this Nano Upgrade Kit.
Nanosuit Upgrade Kit no. 2:
Once you reach a large blue warehouse, turn left and go under the ruined highway bridge. As soon as you pass the bridge you should see a pyramid shaped container. Hack the container and you will get Nanosuit upgrade.
Nanosuit Upgrade Kit no. 3:
Use the Zipline to go down to the ground level. Turn around and you will notice a train wagon. Nanosuit no. 3 is located inside the wagon.