Heat oven to 400°F. In 12-inch nonstick skillet, heat 1 tablespoon of the oil over medium-high heat. Add chicken; cook about 8 minutes, stirring occasionally, until no longer pink in center. Remove chicken from skillet.
Heat remaining 1 tablespoon oil in skillet. Add onion and zucchini; cook and stir about 6 minutes or until zucchini is crisp-tender. Return chicken to skillet (discard chicken juices). Stir in garlic, chili powder, oregano and salt. Cook and stir 2 minutes. Stir in tomatoes; cook until thoroughly heated. Remove from heat.
In small bowl, beat yogurt and flour with wire whisk until blended; stir into chicken mixture. Spoon into ungreased 9-inch glass pie plate.
Unroll pie crust over hot chicken mixture. Fold excess crust under and press to form thick crust edge; flute. Cut slits in several places in crust. Place pie plate on cookie sheet with sides.
Bake 25 to 30 minutes or until crust is golden brown (sauce may bubble slightly over crust). Let stand 5 minutes before serving.