Step 1

Core and quarter 4 medium tomatoes. Place in a blender and add 3 canned chipotle peppers in adobo sauce. Blend until smooth.

Step 2

Halve and thinly slice 1 small white onion (about 1 1/2 cups). Finely chop 2 garlic cloves.

Step 3

Heat 1/4 cup olive oil in a large skillet or medium Dutch oven over medium heat until shimmering. Add the onion and sauté until translucent, about 5 minutes. Add the garlic and cook until fragrant, about 30 seconds. Add 1 teaspoon tomato paste and cook, stirring often, until it evenly coats the onion, 1 to 2 minutes.

Step 4

Nestle 1 1/2 pounds boneless, skinless chicken thighs into the onion mixture. Sprinkle 1 teaspoon dried oregano and 1 teaspoon kosher salt over the chicken. Sauté, stirring occasionally, until the chicken is lightly browned, about 5 minutes. Add the chipotle mixture and stir to combine.

Step 5

Cover and simmer, adjusting the heat as needed, until the chicken is cooked through and flavorful, about 30 minutes. Uncover and shred the chicken with 2 forks into bite-sized pieces directly in the skillet. Taste and season with more kosher salt as needed. Serve with corn tortillas or tostadas.