Preheat oven to 350°F. Spray 9x9x2inch metal baking pan with nonstick spray. Stir 5 ounces bittersweet chocolate, butter, and unsweetened chocolate in medium saucepan over low heat until smooth. Remove from heat. Whisk sugar, eggs, vanilla, and salt in large bowl until fluffy. Stir in melted chocolate mixture. Mix in flour, then nuts and chips; spread in pan. Bake until tester inserted into center comes out with moist crumbs attached, about 35 minutes.
Meanwhile, bring cream to boil in small pan. Remove from heat. Whisk in 3 ounces bittersweet chocolate. Pour glaze over brownies. Chill uncovered 1 hour. Serve cold or at room temperature.