Make the marinadeWhisk together the olive oil, salt, Italian seasoning, minced garlic, and lemon zest in a bowl.
Prepare the chicken. Place chicken breasts in a zip-top bag and pound two at a time until evenly thick, about ½ inch. Uniform thickness matters more than exact thickness. Thickness may adjust cooking time.
Marinate. Add the pounded chicken breasts to the marinade and toss until fully coated. It’s okay if there isn’t much extra liquid. Marinate in the fridge for 3 hours to overnight.
Preheat grill to middle–high heat grilling heat. Nice and hot. Remove chicken from the fridge while the grill heats so the olive oil can liquify again. Grill. Place chicken on the grill, close the lid, and do not touch for 2 minutes. Check for release — if it lifts easily, flip and close. If it sticks, close the lid and cook another ~45 seconds, then try again.
Finish cooking. Grill the second side for 1–2 minutes, or until internal temperature reaches 165°F.Remove from the grill once the chicken releases easily and has good grill marks.