Set the Instant Pot to ‘sauté’ mode, add 1 tbsp olive oil, 2 tbsp garlic, and 2 oz onion to the pot. Stir and cook for 1 minute until the onion is soft and translucent.
Add 18 oz chicken, 1/2 tsp cumin powder, 1 tsp paprika, 1 tsp turmeric, 1/4 tsp garam masala, 1/2 tsp garlic powder, 1 tbsp lemon juice, 1/2 tsp chili powder, 1/2 tsp salt, and 1/2 tbsp mustard. Cook and stir often for 3 minutes.
Add 2 oz peas, 1/4 cup tomato sauce, 2 oz green bell pepper, 2 oz red bell pepper, and 1 tbsp all-purpose flour. Stir to combine and cook for another 2 minutes.
Pour 1 1/2 cup chicken broth into the Instant Pot. Close the lid and set the pot to ‘stew meat’ and set the timer for 7 minutes.
Release the pressure naturally, open the lid, and add 4 tbsp heavy cream. Set the ‘sauté’ mode and let the dish continue simmering until the sauce thickens slightly, about 10 minutes.
Serve the chicken tikka masala warm over steamed rice. Top with 3 tbsp Greek yogurt and 2 tbsp chopped parsley.