Place poblano chile halves, skin sides up, on a foil-lined baking sheet, and flatten with hand. Broil 8 minutes or until blackened. Place peppers in a zip-top plastic bag; seal. Let stand 15 minutes. Peel and discard skins.
Reduce oven temperature to 375°.
Combine chicken and next 11 ingredients (through garlic) in a large bowl; stir in salsa, stirring until well combined.
Place poblano peppers, cut sides up, in an 11 x 7-inch baking dish coated with cooking spray; top evenly with 1/4 cup chips. Spoon the chicken mixture evenly over chips; sprinkle with remaining 1/2 cup chips. Lightly coat chips with cooking spray. Bake at 375° for 20 minutes or until cheese melts and casserole is heated through.