As many frozen boneless skinless chicken breasts as you'd like
Olive oil or whatever cooking oil you keep in your kitchen
Salt and pepper
Other spices to suit your taste
*I've been intentionally vague with ingredients because it will depend on the amount of chicken you want to cook and the flavor profile you want to infuse. The method will be the same no matter what.
Get out as many frozen chicken breasts as you'd like to cook for the day or the week. The only restriction I'd caution you against is to not overcrowd your pan. If you can't fit them all on one baking sheet, you'll get better results by spreading them over two baking sheets than forcing them all together on one. Arrange them with at least two inches of space in between.
I like to use spray oil for this, but you could also brush some oil onto your chicken breasts or just use your hands and then give them a good wash. Add a thin layer of oil to both sides of each chicken breast.
Add salt, pepper, and whatever other spices suit your needs as described in the post above. You can season different chicken breasts for different recipes, but you'll need to be sure to remember which is which when you take them out of the oven later. Be sure to season both sides.
Cover your baking sheet with foil and pop it in the oven. Bake your chicken for 25 minutes.
Remove the chicken from the oven, remove the foil, and use tongs to carefully turn over each chicken breast. Put them back in the oven for a further 20 minutes or until the chicken is cooked through.
Let the chicken rest on the baking sheet for at least 10 minutes before slicing or shredding. You can store the chicken breasts whole as well. I feel like this helps keep some of the moisture in, but if you really want to make things easier later in the week, it's fine to store it pre-chopped.
Store in an air-tight container in the fridge for quick dinner prep later in the week.