Cut chicken into 1½-inch pieces; set aside.

In a bowl, add chopped cilantro, parsley, diced red onion, minced garlic, salt, pepper, and red pepper flakes. Stir to combine. Next, add the red wine vinegar and olive oil. Stir to combine.

Using a food processor or blender add ½ cup of the chimichurri mixture and 2 tablespoons olive oil. Blend until mixture is smooth.

Pour blended mixture over chicken. Stir, making sure all of the chicken is coated. Marinate for 30 minutes.

Heat grill to medium-high heat.

Put chicken onto the skewers. Place on grill. Cook until the chicken easily releases from the grill, 4–5 minutes. Flip the skewers and grill 4–5 minutes more, or until chicken reaches an internal temperature of 165 degrees. Remove from grill. Top skewers with remaining chimichurri sauce.