Press the brown/sauté button on your pressure cooker. When the device is hot, brown the chicken wingettes on both sides. I did this in a few batches.
Add the chicken broth, butter, and garlic on top of the chicken.
Secure the lid. Press the poultry function, set the pressure to HIGH and set the time for 15 minutes. Be sure the steam release valve is in the "Seal" (closed) position. Press start.
When the cooking time is complete, release the pressure by flipping the pressure knob. When the pressure has been released open the lid and drain most the broth off of the broth of the wings, leaving about a 1/4 of broth on the bottom of the presssure cooker under the wingettes.
In a small bowl combine the barbecue sauce, buffalo sauce, chili powder, onion powder and pepper. Pour over the wings.