Heat oven to 375°F. Line cookie sheet or shallow baking pan with cooking parchment paper.
In shallow bowl, stir together bread crumbs and garlic salt. Dip each chicken breast in melted butter; coat with bread crumb mixture. Place on cookie sheet.
Bake 20 to 22 minutes or until juice of chicken is clear when center of thickest part is cut (at least 165°F). Top each chicken breast with 2 mozzarella slices. Bake 2 to 3 minutes longer or until cheese is melted. Remove from oven.
Top each chicken breast with tomato slices; sprinkle with salt and pepper to taste. Sprinkle basil over top. Serve immediately.