Cut the pork into pieces that will fit into the Instant Pot.  Liberally salt and pepper the pork pieces.  Put the oil into the Instant Pot and select saute normal.  Add the pork and brown all the peices on all sides.  Remove and set aside.

Add the onions and cook for about 10 minutes, stirring to prevent burning.  Add the cumin, oregano, garlic powder, lemon and orange juice, jalapenos, and the cola.  Stir to combine and cook on saute for about 10 minutes to reduce a bit.

Press the off button and return the pork to the pot.  Cover and select the meat/stew button.  When it's done cooking and the pressure has released naturally, remove the pork, and select the off button.

Select the saute button and reduce all the liquid by half, about 15 minutes or more, stirring to prevent burning.  Meanwhile, shred the pork and discard any bones.  Return the shredded pork tothe reduced liquid, stir to combine, and cook on saute for an additional 5 or 10 minutes.

Serve on warm tortillas with garnishes of your choice!