Preheat your toaster oven to 350°F. Line a baking pan with parchment paper for easier cleanup.
In a small bowl, mix onion powder, garlic powder, and black pepper. Set aside.
Place chicken breasts on a plate and brush both sides with olive oil.
Sprinkle one side of each chicken breast with half of the salt, then half of the spice mixture. Flip and repeat seasoning on the other side. You'll bake the chicken top side down.
Insert a meat thermometer into the thickest part of the largest chicken breast, sliding it in from the side. The tip should reach the center.
Place the chicken on the pan top side down to promote even browning.
Bake according to chicken breast size.
10-12 oz pieces: 23-26 minutes
Bake until the chicken reaches 165°F.
When chicken reaches 165°F, cover with foil and let sit for 10 minutes before serving. This allows the juices to redistribute for moister chicken breast.
Drain juices from the pan and brush over the chicken before serving.
Add your favorite glaze or sauce and enjoy your quick and easy oven-baked chicken breast!