Season the thighs with the salt, both paprikas and black pepper.
Brown the chicken in the vegetable oil over medium-high heat, 3 minutes per side, and transfer it to a 6-quart slow cooker.
Add the onion, bell peppers, garlic, tomatoes and broth.
Cover and cook on low until the thighs are tender, 6 to 6 1/2 hours.
Move the chicken to a platter and stir the cornstarch mixed with cold water into the vegetables and sauce.
Cook on high for 8 minutes, turn off the cooker and let the bubbling stop.
Stir in the sour cream, return the chicken and serve over the cooked egg noodles.