1. Rub roast with 1 tablespoon taco seasoning on each side. Set electric pressure cooker to sauté function. When hot, add 2 tablespoons olive oil. Place the roast in the pressure cooker to brown on both sides.

2. Temporarily remove roast and add beef stock to the pot. Deglaze the pot using beef stock, scraping until all brown pieces are loosened (not deglazing will cause the pot not to pressurize). Place the roast back into the pot.

3. In a small bowl, combine tomatoes, remaining taco seasoning, chipotle peppers, and vinegar. Pour over roast. 

4. Secure lid onto pressure cooker. Set pressure cooker to seal and to pressure cook on high for 50 minutes. Natural release for 10 minutes before quick release.

5. Remove the roast from the pot and place on a plate. Break into pieces (can also shred with two forks, if desired). Keep warm.

6. Meanwhile, set the pressure cooker back to sauté mode and reduce the sauce to a consistency you like, stirring often to avoid burning (we reduce by about half). Pour over meat or serve alongside.