Preheat oven to 400°F (200°C) and line a baking sheet.
In a bowl, mix cream cheese, pimentos, garlic powder, salt, cayenne, and 1 cup cheddar until smooth.
Slice mini peppers lengthwise and remove seeds.
Fill each pepper half with about 1 tablespoon of the mixture.
Arrange on baking sheet and sprinkle remaining cheddar on top.
Bake Pimento Cheese Stuffed Mini Peppers for 10–12 minutes until cheese is melted.
Let cool slightly, then garnish with sliced chives and serve.