Step 1

In a large pot over medium, heat the oil until shimmering. Add half of the tortilla strips and cook, without stirring, until slightly firm, about 30 seconds. Toss with tongs, then cook, tossing often, until browned and crisp, 2 to 3 minutes. Transfer to a paper towel–lined plate and sprinkle with salt; set aside.

Step 2

To the same pot over medium, add the onion and ½ teaspoon salt, then cook, stirring occasionally, until the onion begins to brown, about 5 minutes. Add the chili powder and cumin; cook, stirring, until fragrant, about 30 seconds.

Step 3

Add the tomatoes with juices and the broth. Bring to a simmer over high, then add the remaining tortilla strips and the chicken breasts. Reduce to medium and simmer, uncovered and stirring occasionally, until the tortillas have broken down and the thickest part of the chicken registers 160°F, 15 to 20 minutes.

Step 4

Remove the pot from the heat, then transfer the chicken to a plate. Using 2 forks, shred the meat into bite-size pieces. Stir the chicken into the pot and cook over medium, stirring, until heated through, about 1 minute.

Step 5

Off heat, stir in the lime juice, then taste and season with salt and pepper. Garnish with the fried tortilla strips and additional chopped onion.