Combine ½ teaspoon Italian seasoning, salt, pepper, 2 tablespoons shredded parmesan, and flour. Coat chicken tenderloins in this mixture. Or sprinkle the seasonings all over the chicken.
In a large Dutch oven or a deep skillet that has a lid, melt butter and add oil. Cook the chicken until fully done. Remove chicken, set aside on a plate, and keep warm.
In the same pot, using the remaining oil/butter, cook onion until soft and translucent (for 2 minutes). Add garlic and cook for an additional minute or until fragrant.
Add pasta to the pot, stirring well to coat it in the liquid. Bring to a boil, then reduce heat, cover, and simmer for 11-13 minutes, stirring intermittently, until pasta is al dente.
The sauce will be thin initially. Add the remaining Italian seasoning and ¾ cup shredded parmesan cheese. Stir well. The sauce will thicken as it cools.