Add pork to a lightly greased pressure cooker/instant pot. Pour coca cola over the pork.
Stir together 2 cups bbq sauce, brown sugar, apple cider vinegar, garlic powder, and onion powder. Pour over pork.
Place lid on the pressure cooker, sliding into the locked position. Set to pressure cook for 45 minutes. Do a natural release for 10 minutes, then turn valve to the vent position. Once float valve has dropped, remove lid.
Use two forks to shred pork into small chunks. Use a slotted spoon to transfer pork to a bowl (discard liquid from pressure cooker) and stir remaining 1/2 cup bbq sauce with shredded pork.
Serve pulled pork on hamburger buns. Optional sandwich toppings to take your pulled pork to the next level: mayo, extra bbq sauce, and cole slaw.
Follow the instructions for preparation for Instant Pot/Pressure Cooker, but to use a slow cooker, cover, and cook on low for 6 hours before shredding pork.
Pro Tip: My favorite tip for choosing bbq sauce is to pick two different flavors - like a sweet + smoky, or a sweet + spicy. I love the depth of flavor it adds to the pork when you use two different kinds of bbq sauce together.From Frozen: If using frozen pork that has not been cut into four chunks, increase pressure cooking time to 1 hr 20 mins to yield fully cooked, very tender pork.