Is it possible for an ordinary citizen to trace source of nuisance calls to cell phone when caller ID has been blocked?
The caller ID you get is what your provider tell you and in turn it's what the caller's provider claims. Even your service provider cannot trace the exact source of the call, it only knows what the caller's provider claims.
So you need the cooperation of your provider to give information about the call (mainly the caller's provider). Then you need the cooperation of the caller's provider and you give them your number and the time of call, then it could be possible for them to identify the caller.
The whole process is nearly impossible for the normal Joe to do. You need help from the authorities. Even then, don't really count on them. Depending on your jurisdiction, unless your caller is a "terrorist" or some high-profile criminal, they likely won't do anything.