Gather your ingredients: slice the chicken into thin strips, dice the bell peppers into strips, and thinly slice the onion. Mince garlic if using.
In a small bowl, toss the chicken slices with smoked paprika, cumin, chili powder, salt, and pepper if desired. Let the seasoned chicken sit while you prep the vegetables.
Heat your large skillet over medium-high heat until it’s shimmering hot. Add a tablespoon of olive oil and swirl to coat the surface.
Add the seasoned chicken to the hot skillet, spreading it out in a single layer. Let it cook undisturbed for about 2-3 minutes until it begins to turn golden and crispy on the edges.
Stir or flip the chicken pieces and cook for another 2-3 minutes until fully cooked through and browned. Transfer the cooked chicken to a plate and set aside.
In the same skillet, add a little more oil if needed, then toss in the sliced peppers and onions. Cook for about 5-7 minutes, stirring occasionally, until the peppers are charred in spots and the onions are soft and fragrant.
Return the cooked chicken to the skillet with the peppers and onions. Toss everything together and cook for another 1-2 minutes to meld the flavors. If using, add the minced garlic now and cook until fragrant, about 30 seconds.
Squeeze fresh lime juice over the skillet mixture, giving it a good toss to brighten the flavors. Turn off the heat and garnish with chopped cilantro and shredded cheese if desired.
Serve the vibrant, smoky chicken fajitas straight from the pan, pairing with tortillas or rice if you like. Enjoy the bold flavors and crispy, tender textures in every bite!