In a large pot of salted boiling water, cook the fettuccine according to package instructions until al dente. Drain and set aside, reserving 1/2 cup of pasta water.
In a large skillet, heat olive oil over medium heat. Add the diced green and red bell peppers and chopped red onion. Sauté for about 5 minutes until vegetables are softened. Add minced garlic and cook for an additional minute until fragrant.
Reduce the heat to low and pour in the heavy cream, stirring gently. Add the shredded Monterey Jack and Parmesan cheese, stirring until melted and smooth.
Stir in cumin, chili powder, salt, and pepper to taste. If the sauce is too thick, add a bit of the reserved pasta water until you reach the desired consistency.
Add the shredded rotisserie chicken to the sauce, mixing well to incorporate. Then toss in the cooked fettuccine, ensuring that the pasta is well coated with the creamy sauce.
Allow the mixture to cook together for another 2-3 minutes, stirring frequently until everything is heated through.
Plate the Southwest Rotisserie Chicken Alfredo and garnish with chopped fresh cilantro for a pop of color and added flavor.