Bring a large pot of salted water to a boil and cook the spaghetti until just al dente according to package directions. Drain well and set the noodles aside.

Cook the chicken, then shred it using two forks. We cooked ours over medium heat, pulling it apart into smaller pieces as it cooked through. You can use whatever method you prefer, or even shred a store-bought rotisserie chicken to save time.

prefer, or even shred a store-bought rotisserie chicken to save time.

In a large skillet or pot, melt the butter over medium heat. Add the diced onion and cook for about 5 minutes, stirring occasionally, until softened.

Add the cubed Velveeta and the can of Rotel tomatoes (with the juice) to the skillet. Stir frequently until the cheese melts and the mixture becomes smooth and creamy.

Add the cooked spaghetti and shredded chicken to the cheese mixture. Stir until the noodles and chicken are evenly coated with the sauce.

Transfer the mixture to the prepared baking dish and spread it out evenly. Sprinkle shredded cheese over the top and bake for 25-30 minutes.

Remove from the oven and sprinkle sliced green onions on top before serving.