Start by trimming your chicken breasts and cutting them into lengthwise strips for faster cooking and seasoning.
In a bowl, combine the lemon zest, lemon juice, Greek seasoning, olive oil, Greek oregano, and black pepper. Add the chicken strips and toss until well coated. Let it marinate for at least 15 minutes.
Set your Instant Pot to the sauté function. Once hot, add the marinated chicken strips in a single layer. Sauté for about 3-4 minutes until they start to brown.
Pour in the chicken stock, scraping up any browned bits from the bottom of the pot to enhance flavor.
Seal the Instant Pot lid and set it to cook on high pressure for 8 minutes. Perform a quick release once the timer goes off.
Remove the chicken from the pot and let it rest. Prepare your bowls with rice, quinoa, or salad, top with the chicken, and garnish with diced cucumbers, tomatoes, red onion, and tzatziki sauce.