Preheat the oven to 400 degrees . In a nonstick skillet with a lid, heat the oil over medium. Add the sweet potatoes and onion. Cover and cook, stirring occasionally, until tender, about 8 minutes. Add the garlic; cook until fragrant, about 1 minute. Using a fork, coarsely mash the mixture; season with salt and pepper. Stir in the black beans and adobo sauce. Cook until the bean mixture is heated through; transfer to a medium bowl.
Wipe the skillet clean and heat over medium-high. Working with 1 tortilla at a time, cook until blistered, about 10 seconds per side.
Divide the bean mixture among the tortillas; sprinkle each with 2 tbsp. cheese. Roll up the tortillas and arrange them, seam side down, in a large (4 qt.) baking dish. Top with the enchilada sauce and the remaining cheese. Bake until the cheese melts and the enchiladas are heated through, about 15 minutes. Top with the pico de gallo and pickled jalapenos.