It takes a little bit of work to merge the nachos486 project code into an existing nachos tree. The following table reflects what was done to add Nachos/486 to the nachos project code:
What this means is that to add Nachos/486 to an existing Nachos project, one must merge in these changes. Fortunately, users are typically forbidden from modifying anything in the machine/ directory, so the files that changed there can probably be copied verbatim from our Nachos/486 code.
In the other files, one has to merge the changes. A tool such as Emacs' ediff-files command will do the job well. Once those changes are merged in, all that remains is to copy the nachos486 directory from a reputable source. Currently the only source of information on the internet is the UVa Nachos/486 FTP site.