Get out a large skillet with deep sides and heat the olive oil in it over medium high heat. Brown the chicken in it until it is cooked through, then add the peppers and onion. Let them become soft and fragrant for another 2minutes or so. While that all cooks, season everything with 1 teaspoon of the taco seasoning, garlic powder, salt and pepper. Pour in the lime juice as well. Let the whole mixture simmer together in the lime juice for another 2-3 minutes, then remove it to a plate and set it aside.

Add the butter and flour to the same pan and whisk them together thoroughly until it becomes a thick, golden mixture. Slowly pour in the milk while you keep whisking, then add the additional 1/2 teaspoon of taco seasoning and Dijon. Turn the heat down to medium and let the sauce simmer for 6-8 minutes, whisking it often. It should become thick and luscious.

In the meantime, get a pot of water on and bring it to a boil for the pasta. Cook it until tender for about 7-8 minutes. Drain it and set it aside for just a minute. The sauce should be done at this point. Whisk in the two cheeses until it is a smooth, gorgeous and cheesy sauce. Stir the chicken, pepper and onion mixture back in too. Finally, stir the pasta in thoroughly to get coated in the cheese sauce. Scoop it into bowls and serve immediately!