Slice bell peppers and onion. Place chicken in the instant pot or pressure cooker. Add bell peppers and onion, and toss.
Top with half of the spices and toss again. Set pressure to high pressure.
Cook for 15 minutes.
Release pressure using the quick release method but flipping the switch to the "venting" position until the metal "pin" sinks down into the lid. (If you don't want to do a quick release pressure cook for 10 minutes, you can decide to do the pressure release naturally and then do a quick release) Drain most of the juice to make the fajitas a bit thicker. It will give quite a bit of juice. Then sprinkle with the other half of the spices.
Plate your chicken fajitas onto tortillas and top with cheese, onion, and a squeeze the lime over top.