The Best Chicken Tinga Tacos

• 1½ lbchicken breasts — poached, shredded, or rotisserie chicken
• 1–2 tbspolive oil
• 1medium onion — diced, 1 cup
• 3garlic — minced
• 2chipotle peppers in adobo sauce
• 1 tbspadobo sauce — from canned chipotle peppers
• 1½ tspdried oregano
• 1 tspcumin
• ¼ tspsalt
• ¾ cupfire-roasted diced tomatoes
• ¼ cupchicken broth — or veggie broth
• ½lime — fresh

For serving:

• —Tortillas
• —Avocado
• —Queso fresco — or cotija cheese
• —onions — finely diced
• —Chopped cilantro
• —Lime wedges