Combine tomatoes, 1/2 cup mozzarella, basil and dry stuffing mix, stirring until just moistened.
Fillet chicken breasts horizontally into ¼- to ½ -inch slices if they are too thick.
Place a generous amount of stuffing mix on each fillet and roll up tightly.
Place in a baking pan with seam side down.
Pour dressing evenly over chicken and sprinkle with remaining mozzarella.
Bake at 350 degrees for 45 minutes.