Heat 2 tablespoons olive oil in a large saucepan or deep skillet over medium-high heat.
Season the chicken pieces with 1/2 teaspoon kosher salt to taste, 1/4 teaspoon chili powder, and 1/4 teaspoon ground cumin.
Add the chicken to the hot pan and cook 5–6 minutes, stirring occasionally, until cooked through; transfer to a plate and set aside.
Add the remaining 1 tablespoon olive oil to the pan, then add the diced onion and diced bell peppers.
Season the vegetables with the remaining 1/4 teaspoon chili powder and 1/4 teaspoon ground cumin and cook over medium-high heat until softened; remove and set aside with the chicken.
Pour the chicken broth, salsa, and heavy cream into the pan and bring to a gentle simmer.
Add the short pasta, stir to combine, cover, and cook 15–20 minutes until the pasta is tender, stirring occasionally and replacing the lid quickly each time.
When the pasta is cooked, stir in the lime juice, return the cooked chicken and vegetables to the pan, and heat until warmed through.
Stir in the shredded cheddar cheese until melted, then serve with optional sour cream, guacamole, and chopped cilantro.
