Whisk first 5 ingredients in a 2-quart pitcher or large bowl until blended. Cover and chill 30 minutes.
Pour milk mixture into freezer container of a 1-quart electric ice-cream maker, and freeze according to manufacturer's instructions. (Instructions and times will vary.)
Stir caramel sauce into prepared ice cream. Remove container with ice cream from ice-cream maker, and place in freezer 15 minutes. Microwave semisweet chocolate morsels and shortening in a microwave-safe glass bowl at HIGH 1 minute. Stir until smooth. Place toasted chopped pecans on a parchment paper-lined baking sheet. Drizzle pecans with melted chocolate. Freeze 5 minutes. Break into bite-size pieces. Stir chocolate-and-pecan pieces into ice cream. Transfer to an airtight container; freeze until firm, about 1 to 1 1/2 hours.
Note: For testing purposes only, we used a Rival 4-quart Durable Plastic Bucket Ice Cream Maker and a Cuisinart Automatic Frozen Yogurt-Ice Cream & Sorbet Maker.