If your chicken breasts are large, slice them in half lengthways to create 4 thinner pieces. Pat the chicken dry with paper towels.
Brush 1 tablespoon of olive oil over all sides of the chicken breasts.
In a small bowl, combine garlic powder, smoked paprika, onion powder, oregano, salt, black pepper, and cayenne. Stir to blend.
Sprinkle the spice mixture evenly over both sides of each chicken breast, pressing gently to adhere.
Heat the remaining 2 tablespoons of olive oil in a large skillet or cast iron pan over medium-high heat until hot.
Place the chicken smooth side down in the skillet and cook undisturbed for 5 minutes until a golden brown crust forms.
Flip the chicken with tongs, reduce the heat to medium, and cook for an additional 2 to 5 minutes depending on thickness, until the internal temperature reaches 160°F to 165°F.
Add the butter to the skillet, then remove the pan from the heat. Let the chicken rest in the pan for 2 minutes to absorb the butter.
Transfer the chicken to a cutting board and let it rest for 5 minutes before slicing against the grain or serving whole.