Most accurate way is to go to Browse foods, instead of Search. Find poultry, then chicken, then breast, then how prepared, then with or without skin. I do chicken breast this way and it comes up to about 45 calories an ounce, cooked, which is probably similar to your 4 oz uncooked (I assume) at about 140 calories (weight is lost during cooking). Alternatively, you could always enter the info from the package as a custom food.
And now that you don't have to be perfect, you can be good.