1Heat oven to 425º. Lightly spray large piece of aluminum foil or ovenproof plate with cooking spray.
2Spread 2 cups of the tortilla chips on foil in 9-inch circle. Sprinkle with about 3/4 cup of the cheese. Top with remaining chips and the bell peppers. Cut chicken strips into smaller pieces if desired; sprinkle over bell peppers. Sprinkle with onions and remaining 1 1/4 cups cheese.
3Bake 6 to 8 minutes or until cheese is melted. Meanwhile, mix salsa and chipotle chilies. Spoon salsa mixture over hot nachos. Serve warm.