In a large pot of boiling salted water, cook pasta according to package instructions until al-dente. Reserve ½ cup of pasta water before draining.
Season chicken breast pieces with fajita seasoning. Heat olive oil in a large heavy-duty skillet over medium-high heat. Add the chicken pieces to the pan and cook for 2-3 minutes or until the chicken is browned and cooked through.
Add the sliced bell peppers, onion, and minced garlic to the pan. Stir for 2-3 minutes or until onion is tender.
Stir in the heavy cream and the reserved pasta water. Bring to a gentle simmer then stir in the pasta and cheese. Stir and simmer for 5 minutes or until the cheese is fully melted and all the flavors are combined.
Top with fresh minced cilantro, serve immediately.
