Open a large ziplock bag, pierce the chicken in several places to allow the marinade to penetrate, and place the chicken inside.
Add 12 ounce bandage pouch in half before zipping to force the air out.
Place the bag in the bowl to avoid spills and refrigerate for at least 4 hours. Drain chicken, discard dressing and pouch.
Heat up the grill. Make sure the grill is clean and oiled, or use Reynolds grill strips.
Cover and grill chicken breasts and grill over 350° to 400° (medium-high) 6 to 7 minutes on each side or until cooked through. Prick the chicken with a knife so that the juice runs clear.
Wrap the tortillas in foil and place them on the grill’s bread rack to warm them up. Place on top of the spinach leaves and drizzle with Italian dressing.