Generously season the chicken all over with 1 tsp. salt and 1/2 tsp. pepper. Add the oil to the multicooker and press sauté. When the oil begins to shimmer, add the chicken and cook, stirring occasionally, until no longer pink, about 7 minutes. Add the onion and celery, and cook, stirring occasionally, until softened, about 2 minutes. Add the garlic and cherry pepper, and cook, stirring, just until fragrant, about 30 seconds. Add the tomatoes, broth, 1/2 tsp. salt, and 1/4 tsp. black pepper, and cook, stirring occasionally, until well combined, about 2 minutes. Add the rigatoni and stir to combine. Using the back of a large spoon, press the pasta into the broth in an even layer. Press cancel.

Secure the lid, making sure that the valve is in the sealed position, and select pressure cook-low pressure. Set the timer for 6 minutes.

Once cooking is done, let sit in the pot for 10 minutes undisturbed, then use the quick-release method to release the remaining steam. Uncover the pot, stir in 2 Tbs. of the parsley, the pepper brine, and butter, and continue to stir until the butter is melted. Season to taste with salt and pepper. Divide among 4 bowls, garnish with the remaining parsley, and serve.