Put a medium pot of salted water on to boil for the pasta and cook pasta according to package instructions.
While your pasta is cooking, in a large skillet, over medium to medium-high heat, melt butter. Add chicken breast, sprinkle with salt, and cook until cooked through. Transfer cooked chicken to a plate and tent with foil to keep warm.
Return pan to heat and add bell pepper and garlic. Cook over medium heat for 4 to 6 minutes, until vegetables just begin to soften.
Add tomatoes and spices, bring to a simmer, and cook, stirring occasionally, until mixture becomes thick and saucy, about 6 to 10 minutes (different brands of tomatoes will vary). Stir in cooked chicken and simmer for 1 minute more or until chicken is hot.