1. Warm oil in a skillet over medium-high heat. Dry chicken; season with salt and pepper. Working in batches, cook chicken in a single layer until golden, turning once, about 10 minutes total. Remove to a plate. Repeat with remaining thighs.
2. Pour off all but 1 Tbsp. fat. Reduce heat to medium and cook onion, stirring, until softened, about 3 minutes. Add a little broth if onion begins to burn. Stir in paprika, tomato paste and chicken broth.
3. Add chicken to skillet. Bring to a simmer over medium-high heat, cover, reduce heat to medium-low and cook 15 minutes. Remove lid and flip thighs. Turn heat to medium and simmer, uncovered, until chicken is cooked through, 10 to 15 minutes. Remove chicken to a platter.
4. Remove skillet from heat. Whisk in sour cream. Season with salt and pepper. Serve chicken and sauce over noodles, if desired.