Season the chicken: Pat the chicken dry and toss with 1 tablespoon of fajita seasoning, a pinch of salt, and pepper. This helps build flavor from the start.
Sear the chicken: Heat 1 tablespoon of olive oil in a large pot over medium-high heat. Add chicken and cook until lightly browned and just cooked through, 4–6 minutes.
Transfer to a plate.
Sauté the veggies: Add the remaining oil to the pot. Add onions and bell peppers with a pinch of salt. Cook, stirring occasionally, until softened and slightly charred at the edges, about 6–8 minutes.
Bloom the spices: Stir in garlic, remaining fajita seasoning, and coriander.
Cook 30–60 seconds until fragrant. Don’t let the garlic burn.
Build the soup base: Pour in chicken broth and crushed tomatoes. Scrape up any browned bits from the bottom of the pot for extra flavor.
Add the mix-ins: Return chicken to the pot.
Stir in black beans and corn. Bring to a gentle boil, then reduce heat and simmer 10–15 minutes to meld flavors.
Finish with freshness: Stir in lime juice and cilantro. If using cream, add it now and warm through without boiling.
Taste and adjust salt and pepper.
Serve: Ladle into bowls and top with avocado, cheese, sour cream, tortilla strips, and sliced jalapeño as you like. A squeeze of extra lime is great here.