In a large Dutch oven over medium heat, add a couple of tablespoons of olive oil.
Meanwhile, cut chicken into chunks and place in a bowl.
Sprinkle with garlic powder, onion powder, paprika, cayenne pepper, and ½ teaspoon each of salt and pepper; toss chicken to coat well with seasonings.
Place the chicken in the hot pan and brown, (in multiple batches if necessary) about 2-5 minutes on each side.
(Chicken does not have to cook all the way through).
Remove from Dutch oven and transfer to a plate (continue with remaining chicken if needed).
Add remaining olive oil to the skillet.
Add mushrooms and cook until brown, about 4 minutes.
Add the leeks, onion and garlic and cook, stirring occasionally, until veggies are soft and translucent—about 2-3 minutes.
Whisk in the butter and flour.
Add the chicken stock, about ¼ cup at a time until all is added.
Whisk until sauce is smooth.
Add Worcestershire sauce, thyme, and the remaining salt and pepper.
Bring to a simmer and allow the sauce to thicken.
Add chicken; turn heat down to low and continue simmering for 5-8 minutes.
Add the cooked egg noodles and the sour cream and stir until combined.
Cook for 2 more minutes.
Check seasonings.
Add salt and pepper to taste.
Remove pan from heat and garnish with fresh parsley, thyme, paprika, and sour cream if desired.