Melt margarine in a saucepan over medium heat; stir brown sugar and salt into the melted margarine. Mix in corn syrup and sweetened condensed milk; cook, stirring occasionally, until mixture reaches 250 degrees F (120 degrees C), 15 to 20 minutes. Remove from heat; fold in pecans. Stir vanilla extract into the caramel mixture.
Drop spoonfuls of caramel onto the prepared baking sheet. Allow caramels to cool until firm.
Cook and stir chocolate chips in a saucepan over medium-low heat until melted and smooth, about 5 minutes. Remove from heat. Dip cooled caramels in the melted chocolate; return to greased baking sheet. Cool until chocolate is set.