1Preheat the oven to 425F
Brush the tortillas on both sides lightly with 1 tablespoon total of the oil. Place them on 2 baking sheets and bake until crisp, 5-7 minutes. Remove from the oven, leaving the tortillas on the trays.
Meanwhile, heat the remaining 1 tablespoon oil in a large skillet over medium-high heat. Thinly slice the scallions, keeping the dark greens separate, and mince the garlic. Add the scallion whites and light green parts to the skillet and cook until translucent, 2 minutes. Add the garlic, chili powder, cumin, oregano, salt, and cayenne and cook for 1 minute more.
2Place half of the scallion-spice mixture in the bowl of a small food processor and set aside. Add the turkey to the remaining scallion-spice mixture in the skillet and cook, breaking the meat up with a wooden spoon, until it is cooked through, 4 to 5 minutes. Meanwhile, if using an ear of corn, cut the kernels off. Add the corn kernels and tomato sauce to the skillet with the browned turkey and cook until most of the liquid is absorbed, 2 to 3 minutes.
Drain and rinse the pinto beans and add them, along with the chicken broth, to the food processor. Pulse until smooth, scraping the sides once or twice if necessary. Grate the cheese.
3Spread 2 tablespoons of the bean mixture on each tortilla and top with about ¼ cup of the turkey mixture. Sprinkle a heaping tablespoon of cheese on top and bake until the bean puree is warmed through and the cheese is melted, 3 to 4 minutes. Remove from oven and sprinkle with the scallion greens. Cut each pizza into quarters with a sharp knife or pizza cutter and serve each with a dollop of the sour cream.