Preheat oven to 350 degrees F.
Melt 3 tablespoons of butter in a 10" oven-safe or cast iron skillet over medium-high heat. Add chicken breasts seasoned and season with 1 teaspoon of black pepper. Cook for 4 minutes on each side. Remove from pan.
Add onion. Saute for 3-4 minutes to soften. Add garlic, Lowry's, red pepper flakes, and the remaining black pepper; combine well. Next stir in cream of chicken soup, 1 cup of each cheese, Rotel, cream cheese, and sprinkle with more red pepper if desired
Bring a large pot of chicken broth (plus 2-3 cups of water) and salt to a boil. Reduce the heat to medium-low, add chicken and simmer for 15 minutes. Try not to let the chicken boil because it will get too tough. Remove the chicken and let cool. Shred it into bite-sized pieces.
Cook the spaghetti in the same chicken broth until al dente (about 9 minutes). Do not overcook. Remove 2 cups of the liquid, drain pasta, and set aside.
Stir in 1 cup of the reserved chicken cooking broth, adding an additional cup if needed. You do not want it to be too dry; the moisture will evaporate in the oven..
Bake uncovered for 30 minutes. At this time, add the remaining cheese and bake for an additional 10-15 minutes. If the cheese on top starts to get too cooked, cover it with foil. Remove skillet from oven and top with fresh parsley. Enjoy!
