As has been noted, when a qualify is added to “chicken salad” the mayo salad version is trumped.
Hell, the url for the McDonald’s one even says “southwest salad with grilled chicken.”
I’ll be honest. I would have made the same error your son did, especially if asked to make it from roasted chicken, and not for a sandwich. I only associate the mayo chicken salad with sandwiches (do people eat it on its own?), but I didn’t really grow up with that style of chicken salad.
More like a chef’s salad than a chicken salad, IMO.
Now send him out to get some shinola and see what he brings back.
Who said it wasn’t going to be eaten on a sandwich?
When we have chicken salad at home, it’s always made from leftover roasted chicken. (Although leftover roasted chicken more often winds up in taquitos, than chicken salad sandwiches.)
Well, if somebody just asked me to make a chicken salad from some leftover roast chicken for them, I would assume what the OP’s son assumed. But, like I said, I didn’t grow up with chicken salad.
My version of the smittenkitchen version of the Zuni Cafe roast chicken dish is amazing.
But that’s not what the OP asked (according to the OP). Note the bolding I added.
OK, I would still have made the same mistake.
ETA: OK, actually, let me take that back. I see what you’re getting at. Yes, “some chicken salad” is different than “a chicken salad.” In that case, yes, I do believe I would have noticed the use of “some” vs “a.”
Be happy the next generation think chicken ON a salad before chicken with lots of mayo= chicken salad.
I’m voting that’s an improvement! (Also I am very happy that chicken ON salad arrived on the scene. A major improvement to my mind, and for my body!)
But I’ve been at deli counters where there are several types of “chicken salad.” How does one describe “chicken salad” that also incorporates cranberry and apples?
Well, shitty for starters.
I think I would have made the same mistake as your son without some reference to it being used in a sandwich. My whole life, I’ve always felt the need to specify “chicken salad sandwich filling” if I mean the mayo-heavy concoction.
And the same is true for tuna, by the way. A tuna salad is lettuce with tuna on top. If you want the creamy version, you want a tuna salad sandwich filling.
I’m in my thirties and grew up in California, for whatever that’s worth.
I know we call it a salad by an alternate definition that included any chopped item with a dressing, but in my mind, a salad defaults to a leafy green.
I associate the OP’s “chicken salad” with a sandwich. If it’s not in a sandwich, then the OP’s son is also correct. Just think of Chinese Chicken Salad, and then drop the “Chinese”. If the OP said: “Make some chicken salad for sandwiches later on”, then the OP’s son would have goofed.
Chicken, tuna, and egg salads are often used in sandwiches, but don’t have to be. Think of “cold plate” lunches, for example.
You might top “a salad” with chicken, or chicken salad.
I know that this kind of thing is common in certain regions and historical times, but I see that menu and my first thought is “I build my own sandwich? Why so much sandwich filling and only one piece of bread?” 
Delicious and what I would want to eat but I agree not “Chicken Salad”. If someone ordered Chicken Salad and got that I think they would be disappointed.
A watch?
[sup]Yes, I know what you meant, but the Shinola name was bought for a watch factory, which has now apparently expanded into leather goods and bicycles as well.[/sup]
This, exactly. Similar to tuna salad or ham salad. Made out of finely chopped chicken, mayo, and possibly some chopped dill pickle, and spread between two slices of bread in a sandwich.
Although I wouldn’t refuse a garden salad with chicken added to it. But that’s what that is, a salad with chicken added.