Brown beef in large skillet, drain, add taco mix, 1/4 cup of water, and salsa, simmer for 5 minutes. Unroll crescent dough and place into 10 inch pie pan to form crust press edges together at seams. Sprinkle cup of crushed corn chips, spoon meat mixture over chips, spread sour cream on top. Cover with cheese slices sprinkle with remaining corn chips. Bake 375 for 25 minutes or until golden brown. Top with lettuce and tomatoes (optional).