Measure ½ pound of smoked trout. Remove and discard the skin, then break the fish into large chunks.
Add the cream cheese, sour cream, and mayonnaise to the bowl of a food processor. Process until smooth.
Add the lemon juice, horseradish, salt, garlic powder, onion powder, smoked paprika, and cayenne pepper to the cream cheese mixture.
Process on low speed until well incorporated.
Add the smoked trout and pulse until the fish is evenly distributed but still has some texture.
Taste and adjust the seasonings if needed.
Transfer the smoked trout dip to an airtight container and refrigerate for at least an hour before serving.
Transfer the dip to a serving bowl, garnish with chives, and serve as desired.