Place the chicken in a small microwaveable dish, putting the thicker parts of the chicken on the outside. Sprinkle with the lemon juice and pepper. Cover with wax paper and microwave for 5 minutes or until no longer pink. Transfer the chicken to a platter. Add the peach slices to the dish and cook on high for 1 to 2 minutes. Remove the slices and reserve cooking liquid. Mix one-fourth cup of wine or champagne with the butter and onions in the dish and cook on high for 1 minute. Stir in the flour and add three tablespoons of the cooking liquid and the rest of the champagne. Cook on high for 3 minutes, stirring after each minute. Serve the chicken breasts and the peach slices with the sauce over noodles.