It's easier than it looks to present two sauces in the same bowl for this shrimp appetizer. Tilt the bowl slightly and put the cocktail sauce in one side. Then carefully tilt the bowl the opposite way and add the sour cream sauce.
In a small bowl, stir together sour cream, horseradish, chives, and lemon juice. Spoon half of the sour cream mixture in one side of a 4-cup shallow serving bowl. Spoon half of the cocktail sauce into the bowl next to the sour cream mixture. Spoon the rest of the sour cream mixture over the sour cream mixture in the bowl and the rest of the cocktail sauce over the cocktail sauce. If desired, cover and chill dip mixture for up to 4 hours before serving.
To serve, place the bowl containing the dip mixture on a platter. Rinse shrimp; pat dry with paper towels. Arrange shrimp around the bowl. Garnish with chives and/or lemon wedges. Makes 30 servings.