Line a 13x9-in. pan with foil; butter the foil with 1 tablespoon butter. Sprinkle with pecans and chocolate chips; set aside. , In a heavy saucepan, melt remaining butter over medium heat. Add the brown sugar, corn syrup and water. Cook and stir until mixture comes to a boil. Stir in milk. Cook, stirring constantly, until a candy thermometer reads 248° (firm-ball stage)., Remove from heat and add vanilla. Pour into prepared pan (do not scrape saucepan). Cool completely before cutting.