To a bowl, add the chicken thighs and season with chili powder, smoked paprika, onion powder, salt, black pepper, red pepper flakes, and olive oil. Mix together and set aside.
In another bowl, whisk together sesame oil, soy sauce, rice vinegar, brown sugar, black pepper, minced garlic, and minced ginger for the teriyaki sauce.
Sear marinated chicken thighs in a hot pan until fully cooked. Remove from pan.
In the same pan, add and simmer the teriyaki sauce, thickening it with a cornstarch slurry.
Coat the chicken in the teriyaki sauce.
In a separate pan, saute minced garlic in melted butter until fragrant. Add soy sauce, oyster sauce, cream, parmesan, salt, pepper, and sugar.
Toss in cooked udon noodles to coat with the butter sauce.
Plate noodles with chicken on top, garnished with green onions and sesame seeds.