Trim brisket so fat is only ¼ inch thick.
Pat brisket dry with paper towels, and season with salt and pepper liberally.
Turn instant pot on to “SAUTE” and add vegetable oil to the liner when it is hot.
Brown the brisket on all sides, about 8-10 minutes, then transfer to a plate.
Add onions, tomato paste, garlic, cumin, paprika, and chili powder, and saute for 5 minutes.
Add remaining ingredients to the pot. Use a wooden spoon to scrape the bottom. Be sure to scrape all the stuff off the bottom so you do not get a burn notice!
Add brisket and any juices back into the pot.
Turn off the saute function, and lock lid into place. Set valve to sealing.
Turn instant pot on to high-pressure, and cook for 1 ½ hours.
When cooking time is over, let pressure naturally release for 15 minutes, then turn valve to “venting” to release remaining pressure.
Turn pot off completely, but leave lid on.
Let meat sit in the pot for 1 hour, in the sauce, to rest.
Transfer meat to a carving board, and tent with foil. Set aside.
Leave sauce in the pot. Use a large spoon to skim excess fat off the surface.
Turn pot back on, to “SAUTE”. And simmer sauce until thickened, about 10 minutes.
Taste, and season with salt and pepper to preference.
Return to the cutting board with the brisket, and slice against the grain into ¼ inch thick pieces.
Serve with thickened sauce spooned over top of the meat.