Press the Sauté button on the Instant Pot and heat 1 tbsp oil. Add couscous and stir-fry 2–4 minutes until couscous is slightly browned. Add water. Press the Cancel button. Lock lid.
Press the Manual or Pressure Cook button and adjust time to 5 minutes. When timer beeps, let pressure release naturally for 5 minutes. Quick-release any additional pressure until float valve drops. Unlock lid. Drain any liquid.
In a medium bowl, combine remaining ingredients, including remaining olive oil. Set aside. Once couscous has cooled, toss it into bowl with other ingredients. Cover and refrigerate overnight until ready to be served chilled.