Hello Jennifer. It is very common to struggle with chicken breasts because boneless, skinless breasts have almost no fat, making them prone to drying out very quickly in the heat of the oven.
One critical step that is often overlooked is evening out the thickness of the meat before baking. Standard chicken breasts are naturally thick on one end and tapered on the other. By the time the thickest center cooks through, the thinner end is inevitably overcooked and tough. To prevent this, place the breasts between two sheets of plastic wrap and gently pound the thicker section with a meat mallet or rolling pin until the entire breast is an even half-inch to three-quarters-inch thickness.
Once they are even, bake them at a high temperature of 450 degrees Fahrenheit for only 12 to 15 minutes. Fast cooking at high heat keeps the interior tender before the moisture can evaporate. Lastly, consider whether your mother might have used bone-in, skin-on chicken breasts for her Sunday dinners. The bone and skin provide an insulating layer and retention of moisture that boneless cuts simply cannot match on their own.