Season the pork with the salt and pepper and brown it in two batches in the oil over medium-high heat, about 6 minutes per batch.
Transfer the pork to a 6-quart slow cooker and add the onion, garlic, tomatoes, broth, cumin, paprika and coriander.
Cover and cook on low for 3 1/2 hours.
Stir in the sweet potatoes and chickpeas, cover again and cook until the pork is tender and the potatoes yield to a spoon, 3 1/2 to 4 hours more.
Stir in the vinegar and let the stew stand uncovered for 10 minutes so the broth settles.
Taste for salt and break apart only the largest pieces of pork before serving.