Cut the chicken into thin strips. Season with 1 tablespoon of taco seasoning.
In a large deep skillet, heat 1 tablespoon olive oil over mediumhigh heat. Transfer the seasoned chicken to the skillet and cook until chicken is browned, about 4-5 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the remaining 1 tablespoon of olive oil over and add the onions and bell peppers. Season with the remaining taco seasoning, and cook, stirring occasionally, until the veggies are slightly soften and become slightly charred.
Keeping the vegetables in the skillet, add the diced tomatoes, green chiles, marinara sauce and milk. Mix together and simmer for 10 minutes.
Meanwhile, bring a large pot of salted water to a boil. Cook pasta according to package directions until al dente. Drain and add to the skillet along with the cooked chicken.
Stir to combine until heated through, about 2 minutes. Serve with grated parmesan cheese, if desired.