Preheat the oven to 400 degree F. Lightly spray a small, nonstick baking sheet with olive oil spray.
In a medium shallow bowl, combine the yogurt, basil, oregano, thyme, garlic powder, salt, and pepper. Stir to mix well.
Put 2 tablespoon of the bread crumbs in another medium shallow bowl. Set beside the yogurt mixture.
Dip 1 chicken breast into the yogurt mixture to coat. Move the breast to the crumbs to coat evenly. Place on the prepared baking sheet. Add the left over 2 tablespoons of crumbs to the bowl. Repeat the process with the second breast. Place on the baking sheet, not touching the other breast.
Bake for 10 minutes. Flip the chicken and bake for 8 to 10 minutes, or until no longer pink. Serve immediately with mustard or marinara sauce on the side, if desired.