Preheat Your Oven: Start by preheating your oven to 375°F (190°C) with a rack positioned in the center. Line a sheet pan with parchment paper for easy cleanup.
Prepare the Filling: Heat the olive oil in a large skillet over medium heat. Add the onion and bell peppers, stirring occasionally, until softened (about 5 minutes). Stir in the garlic and cilantro, cooking for another minute until fragrant. Add the shredded chicken, chicken bouillon, tomato paste, onion powder, garlic powder, kosher salt, and 1 cup of water. Simmer the mixture for 5-8 minutes, stirring often, until the liquid has mostly evaporated but the filling remains moist. Remove from heat and let cool slightly.
Assemble the Empanadas: Place one empanada dough shell on a flat surface. Add a heaping ⅓ cup of filling to one side of the dough, leaving a ¼-inch border around the edge. Beat the egg with 1 tablespoon of water in a small bowl, then brush the edges of the dough with the egg wash. Fold the dough over the filling and press the edges firmly with a fork to seal.
Bake to Perfection: Place the assembled empanadas on the prepared baking sheet. Brush each empanada with the remaining egg wash for a glossy finish. Bake for 35 minutes, or until the empanadas are golden brown and crisp.