In a medium bowl, combine the olive oil, ranch dressing, taco seasoning, lime juice, and white vinegar. Stir well to create a flavorful marinade.

Gently pound the chicken breasts to about ¼ inch thickness for even cooking. This helps ensure that the chicken cooks evenly and stays juicy.

Place the chicken breasts in a gallon-sized ziplock bag and pour the marinade over them. Seal the bag and refrigerate for at least 8 hours, or overnight for maximum flavor. The longer you marinate, the more intense the flavors will be.

When ready to cook, preheat your grill to medium-high heat. A hot grill will give the chicken nice grill marks and a delicious char.

Grill the marinated chicken for 8 to 12 minutes, flipping halfway through, until the chicken is no longer pink in the center and the juices run clear. Use a meat thermometer to ensure the internal temperature reaches 165°F for safety.