Generally speaking, yes, you can microwave chicken with the bones if it has already been cooked. Just make sure that you cover the plate or container with a damp paper towel to keep the meat from drying out.
However, while microwaves are great time-savers, you shouldn’t cook chicken with bones in the microwave. While chicken breasts can be cooked in the microwave, you should remove any large bones from the chicken before microwaving it because the dense bone may keep the area around it from cooking all the way through.