In a large casserole thaw spinach in microwave; approximately 5 minutes; spread thawed spinach in dish and place chicken breasts on top; cover; return to microwave and cook on medium high; approximately 20 minutes or until chicken is done. Remove from microwave, slice cheese and arrange on top of chicken; top with bacon slices. At this point dish may be returned to microwave for approximately 5 minutes until cheese is melted an bacon is done, or if preferred dish can be placed under the broiler in conventional oven until cheese is melted and bacon is crisp; approximately 2-5 minutes.