Papa Bear's stuffed shells

My grandfather died a few years ago.He and I were very close. He was always in the kitchen whipping something up.I contribute my love for simple cooking and food from them.
During special holidays or events my grandfather would make these shells.
They were FANTASTIC!. I cook this little dish from memory, and it doesnt come close to my grandfathers. He was Puerto-Rican so a lot of his cooking influence came from his culture.

1 whole chicken**
1 half onion (doesn't matter what kind)
1/2 c red bell pepper

1/2 c green bell pepper
1 block or bag of fresh Mozarella
1 box of jumbo shells (Conchiglioni)
Kosher Salt
Ground Pepper
Chili powder
Garlic salt

All the seasonings are to your own taste.
Chop the onions and bell pepper into bite sized pieces, set to the side.
Remove the innards(sp?) and toss them, or save them for something else.
Take the entire chicken and put in a large pot fill the pot with enough water so the chicken is covered. Add the bell peppers and onions in the pot with the chicken, along with some kosher salt,pepper, and chili powder.
Boil the chicken until the meat is tender and falling off the bone.
Let the chicken rest, so some of the juices can be redistributed.
Once its cool take out of the pan and proceed to debone the chicken.
Take all the skin off and the bones.
Make sure to take out the gristle also.
Once its set to the side add about a tbsp of Kosher salt, chili powder,Garlic salt, and pepper.
Rip into shreds, and small pieces.
In another pot boil the jumbo pasta shells until they are soft.
Spray a large rect. Pan with cooking spray.
Take a Jumbo shell and stuff with the shredded chicken mixture along with the onions and bell pepper, and set on the pan, repeat this process until all shells are filled.
Cut the mozarella into thin slices and place on top of the shells.
Cover shells with aluminum foil on 375 for 30 minutes or until the cheese is melted.
I sometimes serve these with some Marinara Sauce on the side

** You can also use chicken breast, instead of a whole chicken. I use a whole chicken because the dark meat adds fat to it. If you use chicken breast put 2 tbsp of olive oil in a skillet with the chicken, otherwise it will dry out in the ove.