I love nachos because of their messiness, not in spite of it. Part of the fun is grasping a half-covered chip and hunting around the pile of toppings for the exact one to help complete the perfect bite. Sure, there are hazards. For every ideal combination, you're left with a soggy chip soaked in sour cream—to speak nothing of the horror of the dreaded naked chip—but that's just part of the game. So the worst thing I could do is try to gussy up nachos, hoping to transform the dish into something it's clearly not. But I did hope that I could add some familiar fall vegetables to the mix, all while keeping the mess gloriously intact.
I've known for a while that black beans and sweet potatoes enjoy each other's company, so it didn't seem like such a stretch to add chunks of roasted sweet potato to a bed a refried beans. And since I had the oven on, I added poblanos, serranos, and some garlic. The roasted poblanos took the place usually occupied by canned pickled jalapeños, and the last two were added to a cooling batch of guacamole.
As for the cheese, I knew that liquid cheese (especially this one) was preferable to a covering of shredded cheddar (which always congeals into a greasy blob after a few minutes). But the orange stuff didn't seem quite right for this recipe. Then I remembered full-flavored Oaxacan cheese, which, much like packaged string cheese, can be pulled into long thin strands. (You can usually find it a Mexican grocery store.) Plus, it's best when it's warm but not fully melted, so that you can appreciate the tangy, creamy flavor.