Preheat your oven to 375°F and line a baking sheet with parchment paper.
In a large skillet over medium heat, add the olive oil and sauté the finely chopped chicken breast and scallions until the chicken is browned and cooked through.
Add the fresh spinach to the skillet and cook until completely wilted, then remove from heat and let the mixture cool slightly.
In a medium bowl, whisk the egg and then stir in the cooked chicken-spinach mixture, crumbled feta cheese, sea salt, black pepper, and dried oregano.
Lay one sheet of phyllo dough on a clean surface, lightly brush with a tiny bit of water or oil, and place the second sheet on top.
Spoon the spinach and chicken mixture onto the phyllo, then fold the dough over the filling to create a large rectangle or individual triangles, sealing the edges.
Place the pie on the prepared baking sheet and bake for 20-25 minutes until the pastry is golden brown and crisp.