Line an 8x8-inch baking pan with aluminum foil; spray lightly with non-stick vegetable spray.
In a large saucepan, combine chocolate morsels, condensed milk, and salt. Heat, stirring constantly, until chocolate melts. Remove from heat. Stir in walnuts, caramel topping, and vanilla. Spread evenly in prepared baking pan. Chill for 2 hours or until firm.
Invert onto a cutting board; peel off foil. Cut into squares.