CS arrives at terminal 2A and AF (to Nice) departs at 2F.
It takes time to get from one to the other. Walking is quite complicated and takes about 20min. There is also a bus and that should be a bit faster and easier.
Getting around terminal 2 on foot - PARIS-CDG CHARLES de GAULLE AIRPORT
If you check the bags though, they are likely to take longer, possibly much longer.

There is a good chance that CX will accept to check your bags through on separate tickets.Then you will clear customs at NCE (your bags will not have the green tag showing that you originated in France)..

I suggest that you pad a big transfer time as you will have to clear immigration when arriving at CDG. UNless you are French passport holder (and some EU) who can use the electronic gate, this is a very busy immigration time. Travelling in J would give you fasttrack, but can still be a bit long if you arrive after some other longhaul flights.