I was thinking Christopher James also. That being said my best friend husband's name was Christopher and they named their son Christopher so their sons just little Chris
My friends brother has the same first name as his dad too but they call him by his middle name. Not sure if you’d like doing that but just a suggestion
We are also using James as the middle name I think it really flows with C first names. His first name will be Caladin so he can go by Cal or CJ if he wants a shorter name. Some other options we looked at for more ideas for you were: Scott Michel (family name) Dean Reid Riggs Wade Drake Vance Bryce
Something with a J and can call him “CJ” Christopher James? Just another nickname option