Season both sides of the chicken with salt and pepper
Set Instant Pot to Sauté and heat 1/2 tbsp of oil. Once hot, add the chicken and sear both sides for 2-3 minutes each until brown. Chicken does not need to be cooked through. Once brown, remove chicken from InstaPot and set aside.
Keep the Instant Pot on saute and add 1/2 tbsp of olive oil, onion, garlic, chili powder, and 1/2 tsp of salt. Let cook for about 3 minutes until the onion starts to soften. Turn Instant Pot off of saute mode and stir in the 3 chipotle peppers, diced tomatoes (and their juice), and the chicken that you set aside in step 2.
Try to arrange the chicken in a single layer as best as you can and pour the lime juice over top.
Lock the lid in place and cook in the pressure cooker for 8 minutes. As soon as the time is up, vent immediately. Take chicken out of the InstaPot and shred, while returning the InstaPot to saute for 5-10 minutes allowing the liquid to simmer. Stir the liquid occasionally and once the chicken is shredded, return to the Instant Pot.
Once the sauce is reduced, chicken is done and ready to serve!