Ok, I think I see the confusion here. Lets start with some basics.
The J1772 plug is for level one and level2 charging and supplys AC current to the onboard charger
The Chademo Is DC fast charge only, so Leaf's with fast charge have two sockets on the nose J1772 and Chademo
CCS-1 has BOTH AC and fast charge DC on one plug. CCS stands for "combined charging standard" so only one socket would be required for both AC and DC fast charging.
To adapt a CCS to a Leaf for fast charging you would need a lot of electronics and a Chademo plug to fit to the Leaf.
In Europe, there is CCS-2 which adds being able to charge from three phase sources and has a 3rd current carring wire. We don't have that here, due mainly to the common 3 phase voltage in the US being higher than the plug is rated for.
To Adapt a CCS plug for a Leaf, it requires figuareing out what is powering the CCS plug, is it 240V AC or DC fast charge? Remember the CCS protocol does both, it uses the same plug for high current AC and DC, so the car has to know which device to connect the power too, Straight to the battery for DC input or to the charger for AC input. This is why it is not simple to swap between types. With the J1772 plug and Chademo being completely separate there can be no mix-up.
Most chargers with CCS-1 for level 2 will also have a J1772 option. That is not true where the CCS-1 is used for DC fast charging.
The CCS allows for less room needed for the plug, which is why it is taking over, only one plug slightly bigger than a J1772 will be all that is required. The Chademo system has its advantages as well, but requires its own dedicated socket on the car, and doesn't require the electronics to switch between supplying AC and DC over the same cables (at different times of course).
This may help:
https://en.wikipedia.org/wiki/Combined_Charging_System