I just had one from Starbucks. I know what you're thinking: Why doesn't she look it up on the Starbucks website? I tried that, but if I change from their default milk type and size, it won't display anything at all under the main heading. So, I can get the calories for a grande 2%, but not tall nonfat.
I know it won't be too much, since the only calorie-containing ingredient is the nonfat milk. It would be nice if anyone knows the actual amount, though. Thanks.