Add the sliced onions to the pot and saute until they are golden brown and caramelized. Add a small amount of stock to the pot to deglaze the pan, scraping up the any browns bits on the bottom with a wooden spoon. Add the onions to the slow cooker.
Heat a heavy pot over medium-high heat (or heat a multicooker to 475). Season the pork chunks with salt and pepper, then add them to the pot to brown, approximately 5 minutes per side. Remove from the pot and add to a slow cooker.