Vegetarian sweet potato tacos with onion sour cream

Ingredients

• Dash of vegetable oil, for cooking
• 1/2 cup yellow onion, finely chopped
• 1 tablespoon jalapeño pepper, seeded and finely chopped
• Salt
• pepper
• 1 cup sour cream
• Dash of olive oil, for cooking
• 2 cups sweet potato, peeled and cut into 1/3-inch cubes
• 1/2 cup red pepper, cut into 1/3-inch cubes
• 1 cup canned black beans, drained and rinsed
• 1 cup frozen corn kernels
• 1 teaspoon store-bought chili seasoning
• 1/2 cup chili sauce (usually sold in the same aisle as ketchup)
• 1/4 cup water
• Juice of 1/2 lime
• 1/4 cup fresh cilantro, chopped
• 1 cup Monterey Jack cheese, grated
• 10-12 store-bought soft taco shells