Good question, scale could be the problem. Pulling a few tens of megawatts from the enviroment for a wind farm sized liquid air plant isn't too difficult. Pulling a couple of gigawatts for a nuke is another matter.
I guess you could offset having to take the heat from the enviroment by pumping the heat generated (when you compress the air) into the ground and drawing it back later. That techonology exists as interseasonal heat stores.