Heat oven to 350° F. In a bowl, combine the crackers, cheese, garlic salt, and pepper.Dip the chicken in the butter, then in the cracker mixture, pressing gently to help the crackers adhere. Place the chicken on a foil-lined baking sheet.Sprinkle any remaining cracker mixture on the chicken and drizzle with any remaining butter. Bake until the chicken is golden brown, 25 to 30 minutes.