my husband isnt a chain smoker, but he smoked since he was 13-24. since been smoke free for 1.5 years.
but when he did his first medical, they found a dark area on his lung, so they sent him for additional testing for TB.
everything turned up fine and clean.
but if they see something out of the ordinary, they may ask you to do additonal tests, if so, it might delay the process a couple months. but once you have gone through the testing, they will approve the medical.
so it all depends if something shows up on your xrays or not.