Mix all of the dressing/marinade ingredients together in a bowl. Reserve about ½ of the dressing and set it aside for later. Put the chicken into the bowl with the remaining half of the marinade, cover it with plastic wrap, and let it sit in the fridge for about 30 minutes.
Meanwhile, cover a baking sheet with aluminum foil, spray it with nonstick spray and pre-heat the oven to 400 °F
Arrange the 2 tortillas on the baking sheet, lightly spritz them with nonstick, and sprinkle on the garlic powder and 1 ounce of grated Parmesan. Pop it in the oven for about 2 minutes, until the Parmesan cheese is melted and the tortillas are a little brown around the oven.
While the tortillas are still piping hot, quickly cut them into triangles with a sharp knife, kitchen scissors or a pizza cutter. Set aside
Fire up the grill, discard the excess marinade and cook the chicken until a thermometer registers an internal temperature of 165 °F . You can also do this in a skillet on a stovetop over medium-high heat - again, the chicken is done when the chicken's internal temperature is 165 °F °F .
Let the chicken rest for about 5 minutes before chopping it into bite-size pieces.
Mix the remaining ounce of grated Parmesan into the reserved dressing.
Arrange the spinach, chicken, and tortilla triangles in a bowl. Pour the dressing over the top and mix it all together.