For the Filling:

1. 1. Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
2. 2. In a skillet over medium heat, cook the chicken breasts until no longer pink inside, about 6-7 minutes per side. Let them cool slightly before shredding into bite-sized pieces.
3. 3. In a mixing bowl, combine shredded chicken, cream cheese, shredded cheese, garlic powder, parsley, chives, salt, and pepper. Mix until well combined.

For the Crust:

1. 4. Roll out each thawed puff pastry sheet on a lightly floured surface until about double its original size. Cut into squares approximately four inches by four inches.
2. 5. Spoon about two tablespoons of filling onto the center of each pastry square. Fold over diagonally to create triangles and seal edges by pressing down with a fork.
3. 6. Place filled pastries on the prepared baking sheet. Brush lightly with an egg wash (one beaten egg) if desired for extra shine.
4. 7. Bake in your preheated oven for about 20-25 minutes or until puffed up and golden brown.