In a medium bowl, whisk eggs, milk, dill, salt, and pepper. Stir in tomato, artichokes, olives, feta cheese, and onion. Set aside.
Add egg mixture to a 7-cup glass dish greased with either oil or cooking spray.
Add water to the Instant Pot®. Insert steam rack. Place dish with egg mixture on steam rack. Lock lid.
Press the Manual or Pressure Cook button and adjust cook time to 8 minutes. When timer beeps, let pressure release naturally for 10 minutes. Quick-release any additional pressure until float valve drops and then unlock lid.
Remove dish from pot and let sit 10 minutes. Slice and serve warm.