Preheat the oven to 375°F (190°C). Place the pie crust in a pie dish and set aside.
In a large bowl, mix the drained tuna, shredded cheddar cheese, mayonnaise, sour cream, chopped green onions, garlic powder, black pepper, and Dijon mustard until well combined.
Add the beaten eggs and stir until fully incorporated.
Pour the mixture into the prepared pie crust, spreading it evenly.
Bake for 30–35 minutes or until the top is golden and the center is set.
Remove from the oven and let it cool for a few minutes before slicing.
Serve warm and enjoy!