Heat oven to 375~. Place tortillas on cookie sheet. Bake 5 minutes or until lightly toasted. In small bowl, mix tomatillos, tomatoes, jalapenos, cilantro, juice, garlic, pepper sauce, cumin and salt. Stir in 1 cup cheese. Mix chicken with chili powder, tossing to coat. Spray skillet with Pam. Cook chicken until tender. For each pizza, spreac 1/2 cup tomato mixture on 1 tortilla. Top with chicken, onion wedges and 1/4 cup remaining cheese. Bake 10 to 12 minutes or until cheese is melted.