In a small bowl, combine onion powder, paprika, salt, and pepper. Season chicken thighs generously with this mixture. Set aside while you prepare green beans.
Bring water to a boil in a medium sauce pan. Add green beans and cook for 10 minutes. Drain and set aside.
Melt 2 tablespoons butter in a large skillet over medium heat. Arrange the seasoned chicken thighs in one layer in the skillet. Cook for 5-6 minutes on each side for a total of 10-12 minutes. Adjust timing depending on the thickness of your chicken thighs. Once done transfer chicken to a plate and set aside.
In the same skillet, lower the heat and melt the remaining tablespoon butter. Add chopped parsley, garlic, hot sauce, red crushed chili pepper flakes, and pre-cooked green beans and cook for 4 to 5 minutes, stirring regularly, until cooked to your liking. Add lemon juice and chicken stock and reduce the sauce for a couple of minutes, until slightly thickened.
Add cooked chicken thighs back to the pan and reheat. Adjust seasoning with salt and pepper (if necessary) and serve garnished with more crushed chili pepper and fresh parsley.