Step 1: Line an 8x4 inch loaf pan or a baking sheet with parchment paper, leaving an overhang on the sides for easy lifting. Sprinkle about 1/2 cup of the chopped pecans evenly over the bottom of the prepared pan/paper.
Step 2: In a large microwave-safe bowl, combine the mini marshmallows and caramel sauce. Microwave on high for 60-90 seconds, stirring halfway through, until the marshmallows are puffed and the mixture is melted and smooth. Be careful not to overheat.
Step 3: Add the remaining 1 1/2 cups of chopped pecans to the marshmallow-caramel mixture. Stir well with a spatula until all the pecans are evenly coated and combined.
Step 4: Immediately transfer the mixture to the prepared pan/paper, pressing it firmly and evenly to form a log shape. Use the parchment paper to help compress and mold it.
Step 5: Place the pecan log in the refrigerator for at least 2 hours, or until firm. Once set, use the parchment paper overhang to lift the log from the pan.
Step 6: Slice the pecan log into 1/2-inch thick rounds using a sharp knife. Serve immediately or store in an airtight container in the refrigerator.