In a small bowl, combine the salt, pepper, cumin, oregano, granulated garlic, onion powder, brown sugar, and chili powder.
Season the pork shoulder on all sides, careful not to leave too much seasoning behind.
Press the "saute" function on your instant pot and add some oil. Cook the pork shoulder for 3-4 minutes on each side. Remove the pork shoulder from the instant pot and set it aside.
Add more oil to the instant pot along with the onions and garlic. Stir for 30 seconds and then add the chicken stock, bay leaf, and chipotle sauce. I used the sauce that comes in a can with peppers. Do not add the seeds.
Deglaze the instant pot by scraping the bottom or else you may get a "burn" notice.
Place the pork shoulder back into the pot along with any remaining spices.
Secure the lid, seal the valve, and press the "pressure cook" function. Cook for 90 minutes.
Once the 90 minutes are up, do a quick release by releasing all of the steam. Remove the pork from the instant pot and shred the meat using 2 forks or your fingers. Discard any fat.
Place the meat back into the instant pot and press the "saute" function. Check for seasoning and enjoy with grilled tortillas, raw onions, cilantro, and fresh lime.