Place spaghetti into your Instant Pot in a criss-cross pattern.
Place trivet above spaghetti
In a large mixing bowl, combine chicken, olive oil, 1/2 tsp salt, 1/4 tsp pepper, 1/2 tspgarlic powder, 1/2 tsp onion powder, and 1/2 tbsp Italian seasoning. Stir until chicken is evenly coated.
Place chicken on the trivet above pasta.
Place lid on and pressure on high for 6 minutes.
Allow natural pressure release for 10 minutes, then quick release.Remove chicken. Brush with BBQ sauce, cut into small chunks, and set aside.
Strain pasta.While still in the strainer, add diced tomatoes to the pasta. Stir, allowing the tomato juice to strain as well.
Pour heavy whipping cream into your empty pot with 1/2 tsp salt, 1/4 tsp pepper, 1/2tsp garlic powder, 1/2 tsp onion powder, and 1/2 tbsp Italian seasoning.
Saute on high.
Next, add 1 cup shredded cheddar cheese. Stir contents together and allow to cook for 3 minutes.
Add remaining 1 cup of cheese and stir together.
Bring to a boil, stirring often. Allow to cook and thicken for about 5 minutes. Continue stirring often.
Add pasta and tomatoes.
Stir together until the pasta is coated with sauce.
Add chicken and serve