Season the oxtail with salt, black pepper, garlic and chili powder.
Turn on the Instant Pot ON. Select “Sauté” mode and adjust to more. When it is hot, add the oil. Brown the oxtail few minutes on each side. Press “Cancel”.
Add the barbecue sauce, beef broth and liquid smoke (if using); mix to combine.
Secure the lid to the pot and select “manual” or “high pressure” and cook for 40 minutes.
When the time is over, let the pressure release on its own for 15 minutes. Then, carefully turn the valve to “Venting,” to release any extra pressure that might still be in there. Then remove the lid. Press “cancel”.
If desired, using 2 forks, strip the meat from the bones and return to the pot, discarding the bones.
Serve with creamy mash potatoes and steamed greens. Or on buns to make sandwiches.