Prepare the Chimichurri sauce by combining all of the ingredients in a bowl in the order listed. Stir together, cover, and refrigerate for 2 hours or overnight.
Place chicken into a mixing bowl and add ½ tsp salt and half of the prepared Chimichurri sauce. Cover and marinate for 15 minutes or refrigerate overnight if making ahead.*
To Grill the Chicken: Preheat the grill over medium/high heat. Place chicken smooth-side-down on the hot grates, cover, and grill for 5-7 minutes per side, or until the internal temperature reaches 165˚F at the thickest point with an instant-read thermometer.
To Sautee the Chicken: Preheat a heavy skillet over medium heat and add 1 Tbsp olive oil. Add chicken smooth-side-down and sautee 5-7 minutes per side or until cooked through and 165˚F at the thickest point.
To Serve the chicken, arrange it on a platter and spoon on the remaining chimichurri sauce then serve right away.
