During the Crysis 3 Mission 2: Welcome to the Jungle, you can collect three Nanosuit Upgrade Kits.
Nano Upgrade Kit no. 1:
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.