Vegetarian Chickpea & Potato Tacos

1. For the crispy Tajin chickpeas: Toss chickpeas in olive oil and Tajin. Roast for 25 minutes at 425°F. 
2. For the poblano peppers and potatoes: Sauté them in a cast iron pan, covered, for 7-8 minutes. Add some garlic powder and onion powder during sautéing. 
3. For the charred scallion: Cut the scallions into a few pieces and fry each side in butter on medium-high heat for a couple of minutes per side. 
4. Warm tortillas in a pan over the stove. 
5. Assemble tacos with the crispy Tajin chickpeas, sautéed poblano peppers and potatoes, charred scallions, arugula, cherry tomatoes, pickled red onions, and Greek yogurt (as a "sour cream").