Is Two hours of transit at Atlanta airport enough to catch the other flight? [duplicate]

Provided that all parts of your journey are booked onto the same ticket, the best advice that can be given is: Relax!

Airports and airlines have minimum connection times, and you would not have been able to buy the ticket if the minimum connection time would not be met for your connection. If because of a delay in your incoming flight or long queues at immigration (if you arrive with a non-domestic flight from a non-pre-clearance place), you will miss your outgoing flight, you will be re-booked free of charge by the airline. Obviously you will arrive later then, but at least it doesn't cost anything extra. Also note that before departure of your first flight, that flight is announced to be delayed significantly, you can approach the staff of the airline before departure to already ask for a re-booking.

As already written, if your flight legs are on separate tickets, this does not apply. In fact, 2 hours is rather short unless you are travelling with hand luggage only.