1.Butter 8-inch square pan; set aside. Place chocolate and chips in medium microwavable bowl. Microwave on HIGH 1 minute; stir. Microwave for 30-second intervals, stirring after each interval, until mixture is melted and smooth.
2.Add condensed milk, chopped pecans and vanilla; stir until well blended. Spread in prepared pan. Score fudge into squares with knife. Place pecan half on each square, if desired. Refrigerate until firm.
3.Cut fudge into squares along score marks. Store in refrigerator. Bring to room temperature before serving.
Gift Idea: For a tasty housewarming gift, place the fudge on a pretty glass or crystal serving plate. Wrap it with cellophane and tie with ribbons.