Preheat your oven to 350°F (175°C). Slice croissants in half horizontally.

Scoop out some of the soft bread from the inside of both halves of each croissant to create a well.

In a medium bowl, combine shredded cooked chicken, mayonnaise, shredded cheddar cheese, chopped green onions, garlic powder, salt, and pepper. Mix well.

Spoon the chicken mixture evenly into the hollowed-out croissant halves.

Gently brush the croissants with the beaten egg.

Place filled croissant boats on a baking sheet lined with parchment paper. Bake for 12-15 minutes, or until golden brown and filling is heated through and bubbly.

Let cool slightly before serving warm.