Heat a large skillet over medium heat and add 2 teaspoons olive oil and the diced tortillas. Cook tortillas until browned, 5 minutes. Remove tortillas from the skillet.Add 1 teaspoon olive oil and all the diced vegetables and cook until vegetables have softened, 5-7 minutes. Add the garlic and cook for another minute.Add back in the tortillas and the tomato sauce and let simmer. Next, add in ¾ cups cheese and stir until melted, 2-3 minutes. Top with the remaining ¼ cup cheese and cover until melted. Garnish with fresh basil, if desired.