Brush on side of each pita bread with oil. Place on an ungreased baking sheet. Bake at 350 for 12-15 minutes or until browned and crisp.
Meanwhile, in a small bowl, mash the avocado with lemon juice, salt, garlic powder, and hot pepper sauce. Spread over pitas. Layer with chicken, tomato, and cheese. Bake for 5-6 minutes or until cheese is melted.