Preheat oven to 350 degrees. Heat the butterscotch morsels and the butter in a large saucepan over low heat, stirring often until smooth. Transfer mixture to a large mixing bowl.
Add the light brown sugar, eggs, and vanilla; stir until mixed. Stir in the flour, oats, nuts, and salt, mixing well. Pour into a 13 x 9-inch pan that has been sprayed with nonstick cooking spray. Bake 25-30 minutes or until a wooden toothpick inserted in center comes out clean.