This is a remix (of sorts) of one of my own designs, the Nexus 70mm fan mount for the original Xbox. 

The Nexus 70mm fan works quite well in the original Xbox, however I've had folks ask me about using the Noctua 60mm fan instead. This is primarily for 2 reasons: 1. The Noctua is slightly quieter than the Nexus. 2. Noctua fans are readily and easily available worldwide, whereas the Nexus fan are apparently difficult to source in certain parts of the world. 

This mount is split into 2 parts to allow for easier printing with out a bunch of support material. Print each part as orientated with their flat sides down and then use the standard Noctua include fan screws to mount each piece to the fan as shown in the photos. 

This design has the rear tabs that slide down into the case rear and indents for the tabs on each side of the original fan. This will keep the fan locked into place and not move. Be careful when removing your original fan as to not break those tabs off. The console is 20 years old now. 

This will be available in the near future to purchase from my shop: https://retrofrog.net/

Note: The fan that you want is the Noctua 60mm 12V version: https://amzn.to/3qJS8VL (affiliate link). Other 60mm fans will probably work as well, but the mount was designed with the Noctua in mind.