Boil the whole chicken in a large pot until fully cooked.
Remove the chicken from the pot and allow it to cool.
Once cooled, remove the chicken meat from the bones and shred it into bite-sized pieces.
In the same pot of water used to boil the chicken, cook the spaghetti according to package instructions.
Drain the spaghetti, but do not rinse it.
In a skillet, sauté the diced onion until it becomes translucent.
In a large mixing bowl, combine the Rotel tomatoes with chilies, cream of mushroom soup, diced Velveeta cheese, sautéed onion, and cooked spaghetti.
Mix well.
Transfer the mixture into a greased casserole dish.
Bake in the preheated oven for 30-40 minutes, or until the Velveeta cheese is melted and the casserole is heated through.
Remove the casserole from the oven and garnish with shredded Cheddar cheese.
Serve hot.
Notes / Tips / Wine Advice:
Serving Tip:Serve hot with a side salad or steamed vegetables for a complete meal.Wine Advice:Pair this comforting casserole with a crisp Pinot Grigio or a light-bodied Merlot.