Heat oil in a large Dutch oven over medium-high heat and sear chicken pieces until browned on both sides, then remove and set aside.
Sauté chopped onions in the remaining fat until translucent and lightly golden, approximately 8 minutes.
Stir in minced garlic and cook for 1 minute.
Remove the pot from heat and stir in the Hungarian paprika, salt, and pepper to prevent scorching.
Return to heat and add chicken broth, diced tomato, and diced bell pepper.
Return the chicken to the pot, cover, and simmer on low heat for 30 minutes or until chicken is tender.
In a small bowl, whisk together sour cream and flour until smooth.
Temper the sour cream mixture by whisking in 1/4 cup of the hot cooking liquid, then stir the mixture into the pot.
Simmer for 5 minutes until the sauce has thickened and serve immediately over nokedli or egg noodles.