Spread 1 cup pecans into a 9-inch circle on a lightly greased baking sheet.
Bring sugar and next 3 ingredients to a boil in a heavy saucepan over medium heat, stirring constantly. Cook until mixture is golden brown and a candy thermometer registers 290° to 310° (about 15 minutes). Pour sugar mixture over pecans on baking sheet.
Sprinkle with morsels; let stand 30 seconds. Spread melted morsels evenly over top; sprinkle with remaining 1/2 cup chopped pecans. Chill 1 hour. Break into bite-size pieces. Store in an airtight container.