Place chicken in a single layer in a 9x13" pan lightly sprayed with nonstick cooking spray. Sprinkle with salt. In a skillet, cook and stir bell peppers and onion in oil until tender. Stir in picante sauce and chili powder. Spoon mixture evenly over chicken; cover pan tightly with foil. Bake at 350 degrees for 30 minutes. Remove foil; sprinkle with cheese. Bake uncovered just until cheese melts. Serve with rice or mashed potatoes.