Follow package directions to cook the rotini pasta to al dente. Drain, rinse in cold water, and set aside.
Meanwhile, dice the onion and mince the garlic.
Place a large pot on the stovetop and turn to medium high heat. Add in the oil and onion. Sauté for a few minutes until tender. Add in the garlic and stir for about 30 seconds.
Add in the tomato paste, undrained diced tomatoes, chicken stock, and seasonings (parsley, Italian seasoning, oregano, paprika, salt and pepper to taste (I do about 1/2 tsp. pepper and 1/4 tsp. salt).
Mix and heat through and then bring to a simmer over medium heat.
Stir in the prepared rotisserie chicken and heat through. Taste and adjust seasonings to preference (salt and pepper here again if desired and/or feel free to increase any amounts of those seasonings).
Serve soup with a generous spoonful of the pasta mixed in, freshly-grated Parmesan cheese, and fresh basil
(I like to keep the pasta separate as opposed to mixing it all in the soup in case of leftovers so it doesn’t get soggy. If you plan on eating all the soup in one day, mix all the pasta in when you add in the chicken.)