Place the spaghettini noodles in a boiling pot of water; cook for about 5 minutes as it will continue to cook once placed in the crock pot; set aside.
Dice peppers and onion; add to the crock pot along with the can of Cream of Mushroom soup.
Add spices and 1 cup of the grated cheese; mix to combine and place the chicken breasts on top.
Place the lid on top and and set the crock pot, on low for 6 - 7 hours or on high for 3 - 4 hours.
After a few hours, remove the chicken breasts and shred with 2 forks; it is ok for the chicken to be chunky but not too chunky.
After shredding, return the chicken to the crock pot with the remaining 2 cups of cheese and the cooked spaghettini noodles.
Give it a little mix around and add a few splashes of chicken stock, if desired, and use a few pinches of red chili flakes if you want a bit of heat.
Add salt and pepper, to taste; place the lid back on the crock pot and allow to cook for another 2 to 5 minutes.