Normally I would just say "only on the suspension parts you change", however, a large lift with especially large tires may push you towards other components that the dealership could potentially say are effected negatively in the driveline other than the suspension components, and of course things like axle shafts.
The rest of your warranty shouldn't be effected regardless. As someone mentioned, you could have the dealership do it, which often means the dealer won't even work on it themselves, they often have a 3rd party lift shop do the work, but at least will warranty everything. I've seen some giant lifts done on new trucks sitting on dealers lots, but they will overprice it like crazy.
Also, as mentioned the Magnusson act comes into play, but what can sometimes happen is the dealership will just say no and you in reality will have to prove it, often in court. The dealer will just on their hands and force you to act however way you can. Not like you can call the cops and force the dealer to do the work. They won't do anything they think they don't have to and will force you to prove it, either to corporate or make a small claims case out of it.