In a large bowl, combine the Italian dressing and thick teriyaki sauce. Mix well to create a marinade. Add the boneless, skinless chicken breasts to the bowl, making sure they are fully coated in the marinade. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes.
If you're using a grill, preheat it to medium-high heat. If you're using a skillet, place it over medium heat and add a drizzle of olive oil to prevent sticking.
Once your grill or skillet is hot, remove the chicken from the marinade, allowing any excess liquid to drip off. Place the chicken on the grill or in the skillet. Cook for about 6-7 minutes on each side, until the internal temperature reaches 165°F (75°C).
Once cooked, remove the chicken from the heat and let it rest for a few minutes to allow the juices to redistribute.
After resting, slice the chicken into strips and serve it on a platter. Drizzle any leftover teriyaki sauce from the marinade over the top.
