I also prefer a simple chicken salad if I'm going to eat it in a sandwich (just celery, mayo and lettuce in a good roll or on good bread). And ONLY Hellmann's mayo. Weird vegan "mayo" and Miracle Whip aren't allowed in our house. But if I'm serving it on a plate, or in lettuce cups, I like adding walnuts and chopped green grapes. I love Ina Garten's recipe.
However, to me, the thing that is most important is how you cook the chicken. I don't approve of the Pioneer Woman's method (boiling the chicken for a lengthy time, even if she does turn the heat down). In my opinion that makes the chicken tough. Instead, I poach the chicken and it turns out wonderfully tender.
Here's how I do it.
First, use a sharp knife to horizontally split the boneless, skinless chicken breasts in half, like a book, if they're thick. You just don't want them really thick. No need to pound them.
Then place the chicken in a large pot filled with cold water. Make sure the water covers all the chicken. You can poach one or several as long as the water completely covers the chicken without it being crowded.
Bring the water to a boil. It's important to make sure that the water doesn't just bubble around the edges - the bubbles must break the surface of the water. You should watch it at this point because you need to act as soon as the boil begins.
Immediately when the water reaches a full boil, take the pot completely off the heat and cover it tightly with a tight fitting lid. Now, no peeking!
Just let the chicken in the pot sit off the heat, until you can place your hand on the pot comfortably. A small pot with a single breast won't take long, but if you're poaching a whole chicken or several breasts it can take longer, so plan ahead.
Now remove the chicken and cut it up to your desired size for the salad. You will be amazed at how tender it is, never rubbery, never tough.
Some cooks like to season the poaching liquid, with wine or herbs or vegetables, but I don't. Just cold water and chicken.