This is a remix of hot end case made by the user Ghost13374tw on Thingiverse (which is also a remix):
I just added ventilation holes to the fron for a better ventilation since otherwise the airflow from the cooling fan influences the nozzle temperature.
I have tried several hot end cases and this is in my opinion the optimal solution. There are much better case but they are either not effective or they involve greater redesign. Probably the best is the MK4 hot end design, if you are interested. So this is the “best" of the “simple way”.
The author remixed this model.