
If using portobello mushrooms, use a small spoon to scrape out and discard the gills. Cut into thin strips. If using other mushrooms, roughly chop or slice them. Place in a large bowl.
In a small bowl, stir together 1 tablespoon of the oil, soy sauce, garlic, chili powder, cumin, black pepper, and chipotle pepper. Pour over the mushrooms. With your hands, toss to coat the mushrooms as evenly as you can. They will seem quite dry.
Heat the remaining ½ tablespoon oil in a large skillet over medium-high heat. Once it’s hot and shimmering, add the mushrooms and spread them into a single layer. Saute, stirring occasionally, until the mushrooms are softened and brown and crisping in a few places, about 10 minutes.
Warm the tortillas in a dry skillet, your oven, or in the microwave. Fill with the mushrooms and add your favorite toppings to assemble the tacos. Enjoy immediately.