Bring a large pot of salted water to a boil and cook the spaghetti according to package directions until al dente; drain and set aside.
Return the empty pot to medium heat, add the olive oil and swirl to coat the bottom.
Season the chicken cutlets with salt and pepper, then brown in the oil 2–3 minutes per side until cooked through; remove and set aside to rest.
Sauté the diced onion and bell peppers in the pot 4–5 minutes, until mostly tender.
Stir in the diced green chiles, alfredo sauce, cumin, chili powder, garlic powder, and 1 cup chicken broth.
Cut the browned chicken into bite-size pieces and add it to the sauce.
Taste and adjust seasoning with salt and pepper as needed, then add the cooked spaghetti and grated cheddar; toss until the pasta is fully coated.
If the sauce thickens too much, loosen with a few splashes of chicken broth or milk until you reach the desired consistency.
Sprinkle with chopped cilantro if using and serve warm.
