Heat a skillet over medium heat and add diced onions. Sauté for 5-7 minutes until golden and translucent, then stir in minced garlic, chopped chipotle pepper, cumin, and chili powder, cooking for an additional 1-2 minutes until fragrant and combined.

Add the drained black beans and vegetable broth to the skillet, mashing them lightly with a fork or potato masher. Allow the mixture to simmer for about 5-8 minutes, stirring occasionally until thickened.

While the filling is simmering, stack your corn tortillas and wrap them in a damp paper towel. Microwave them on high for 30 seconds.

Preheat your oven to 400°F (200°C). On a baking sheet, lay out the steamed tortillas and spoon the black bean mixture onto one side of each tortilla. Sprinkle with shredded cheese if desired, then fold them in half.

Place the baking sheet in the preheated oven and bake the tacos for about 15-20 minutes until golden brown and crispy, flipping them halfway through.

Once golden and crispy, remove the tacos from the oven and let them cool for a few minutes. Serve warm with your favorite toppings.