Preparing the Dressing: In a blender jar, combine mayonnaise, buttermilk, salsa, cilantro, lime juice, garlic, garlic powder, onion powder, salt, pepper, and red pepper flakes. Pulse until well combined. Refrigerate for several hours or overnight.
Select Sauté function on the Instant Pot. When hot, add oil and onion to pot. Sauté onion for 3 minutes.
Add chicken and sauté for 2 minutes. Add tomatoes, salt, cumin, and black pepper.
Lock the lid in place. Select Manual on the Instant Pot and adjust to high pressure. Set to 2 minutes cook time. When timer beeps, use a quick pressure release to release the pressure.
Remove the lid. Select sauté and cook stirring frequently, until liquid has cooked off. Stir in black beans and cilantro.
Serve over lettuce topped with chicken, cilantro lime rice, cheese, avocado, crushed tortilla chips, and cilantro lime dressing.
To Make the Cilantro Lime Rice
Add the rice, water, 1 tablespoon oil and salt to the pressure cooker pot. Stir. Lock lid in place. Select high pressure and 3 minutes cook time. When timer beeps, turn pressure cooker off and use a natural pressure release for 7 minutes. After 7 minutes do a quick pressure release.
Fluff rice with a fork. In a medium bowl, combine chopped cilantro, lime juice, and 1 tablespoon oil. Add rice and toss until thoroughly mixed.