What I do is replace the ground beef with the chicken breast, and I ask them to not include the taco shell so I'm not tempted to eat it. If you go to the Nutrition website, remove the beef, shell, sour cream (and those little lime strips, ick) and add two chicken portions from a chicken taco (that's what they use for the salads), you'll get the above 330 calories, etc.
Granted, this is not a regular addition to my diet, but it works. So does a grilled chicken caesar salad from McDonalds.... but modifications again. No dressing. I'd rather just eat at home!