Place the chicken breasts between two sheets of plastic wrap. Use a meat mallet or rolling pin to pound them to an even thickness, about ½ inch thick.
In a shallow dish, combine the flour, salt, pepper, and garlic powder. Dredge each chicken breast in the flour mixture, shaking off any excess.
In a large skillet, heat the olive oil over medium-high heat. Once shimmering, add the chicken breasts in a single layer. Cook for about 4-5 minutes on each side until golden brown and cooked through. Transfer the chicken to a plate and keep warm.
In the same skillet, add the butter. Once melted, deglaze the pan with the chicken broth and lemon juice, scraping up any browned bits from the bottom.
Stir in the capers and allow the sauce to simmer for 2-3 minutes until slightly thickened.
Return the chicken to the skillet, cooking for an additional minute to coat with the sauce.
Remove from heat and garnish with fresh parsley before serving.