Preheat the oven to 450°F. Line a rimmed baking dish with foil or lightly grease it.
Generously spray or brush both sides of each chicken breast with olive oil.
Sprinkle the chicken with kosher salt, black pepper, garlic powder, onion powder, paprika, and dried oregano.
Bake the chicken, uncovered, until the internal temperature reaches 165°F and juices run clear when pierced with a fork, about 20 minutes. The center of the chicken pieces should be white and opaque.
Transfer the chicken to a platter. Loosely cover it with foil and allow it to rest for 5-10 minutes before slicing and serving.
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Notes
If your chicken pieces are much larger than 8 ounces, you will need to bake them for around 30 minutes. So check after 20 minutes, and if you do need to bake them for longer, loosely cover them with foil to prevent the tops from burning.
The best way to make sure the chicken is done is to use an instant-read thermometer inserted into the thickest part. Aim for an internal temperature of 165°F.
You can keep the leftovers in an airtight container in the fridge for up to four days. You can also freeze them for up to three months. If you'd like to reheat the leftovers, do so gently, covered, in the microwave at 50% power. The leftovers can easily dry out when reheated, so I typically use them cold. They make the perfect salad topping.