In a ziplock bag or bowl, place the garlic, italian dressing, soy sauce, and chicken breast to marinate, about ten minutes.
It would be best to heat skillet over medium high and olive oil now. Remove chicken from bag and cut into strips length wise, and then once horizontally. Add to preheated skillet and cook until done, but not over done. Set aside to let juices re-absorb and cool.
With the same skillet, add the rest of the olive oil. Add the vegetables and grilluntil tender and brown, but not burnt. Add the fajita seasoning (I am liberal, and this is the only salt used in the dish -- do not add your own).
With the veggies cooking, shred chicken and add after you add the fajita seasoning. Remove from heat.
In a small round cake dish, spray with non stick cooking spray and place one flour tortilla on the bottom. Add 1 Tablespoon of Taco Sauce, Chicken mixture, and a small amount of cheese.
Place second tortilla and repeat--taco sauce, chicken mixture, and cheese with remainder of shells. It is okay to have left over chicken mixture.
Around the shells, fill with salsa and remainder chicken mixture.
Cover with foil and bake at 350 Degrees for 10 minutes. Remove foil, Sprinkle with extra cheese and bake until bubbly.
Top with sour cream.