Cook pasta according to package instructions, until al dente. Drain pasta but reserve about ¼ cup of pasta water. Return drained pasta to pot and set aside.
While pasta is cooking, heat olive oil in a large sauce pan over medium high heat. When hot, add the diced onion and bell peppers. Season to taste with salt and pepper. Cook, stirring frequently, until soft and golden, about 8 minutes.
Add the garlic and stir until fragrant, about 30 seconds.
Add the beans and corn, cook until heated through, about 1 minute.
Add the cooked chicken and the taco seasoning. Stir until everything is combined and coated with the taco seasoning. Pour in salsa and stir to combine. If the mixture is too dry, add a tablespoon or two of the reserved pasta water.
Pour the entire chicken mixture into the pot containing the pasta. Add the shredded cheese and stir to combine, until cheese is melted and fully mixed in.
Taste and season with salt and pepper if desired.
Garnish with chopped cilantro if desired and serve.
