1.Preheat an oven to 400 degrees F. Poke sides throughout the sweet potatoes and lightly oil. Bake in a glass baking dish for 45-60 minutes until they can be easily cut down the middle.
2. Cut the chuck roast into 4-6 equal sized chunks and season with salt & pepper. Set the Instant pot to saute mode and brown all sides. Set aside temporarily.
3. While still in saute mode add a bit of oil and the veggies, saute for 2-3 minutes.
4. In a mixing bowl, combine all the ingredients for the sauce.
5. Add all the ingredients back to the instant pot, except for the lime sour cream & cilantro for garnish. Set the instant pot to pressure cook for 30 minutes.
6. Remove the meat chunks and shred on a large cutting board or bowl. Transfer them back to the pot and mix with the veggies and liquids.
7. In a small bowl, combine the sour cream ingredients. Transfer to a condiment container if desired.
8. Stuff the sweet potato with the beef mixture and top with the lime sour cream & fresh cilantro!