Spray a 9 x 13 inch pan with non stick cooking spray and preheat oven to 350 degrees.
Melt 1½ cups chocolate chips and butter in a large bowl in the microwave in 30 second increments, stirring in between.
Stir in eggs, then add in flour, sugar, baking soda and vanilla. Stir together well.
Spread batter into the greased pan, then sprinkle with chocolate chips and chopped nuts.
Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Microwave caramels and milk in a small bowl for about 1 minute. Stir and then continue to microwave, stirring every 15 seconds until all is melted and smooth. Drizzle over warm brownies.
Cool brownies before cutting and serving.
