Gently mix all ingredients for the chicken sausage in a large bowl and then set aside.
Heat olive oil in a large Dutch oven or deep skillet over medium-high heat. Pour in the chicken sausage mix and start breaking apart into bite-sized pieces. Once fully cooked, remove the chicken sausage to a plate and set aside.
In the same skillet, add the onions and sauté for a few minutes, or until they’re starting to soften. Next add the garlic and continue to sauté until fragrant. About 1 additional minute. Then add the flour and stir to coat for another minute.
Pour in the chicken stock, tomato sauce, basil pesto, Italian seasoning, bay leaf, chicken sausage, and bring to a low boil. Once boiling, add the pasta shells and simmer for 8 minutes, or until the recommended al dente on the box.
One minute before the pasta is done, go ahead and add the warmed heavy cream, kale, and grated parmesan. Stir. Continue to simmer for another 1 - 2 minutes or until kale has slightly wilted.
Taste, season with salt and pepper, and then serve immediately.