It depends what nes.lib represents in that case. The last time I checked those sample it was almost a year ago so my memory is quite fuzzy about it. I think in that case it would be the C runtime, which you need to rebuild with ca65/cc65, which is not obvious is you just started worked on the nes or have never worked with cc65 directly.
I will check what was nes.lib for alter ego and let you know later.
edit:
I confirmed and nes.lib is the C runtime and alter ago provides a version for cc65 he used at the time. You will need to rebuild that file, which I did once and is a barebone set of the C library but I don't have the commands in front of me to do it. There was a sample I shared last year on nesdev that should allow to re-create it and may contain the sample with it. I will see if I can find the link and add it to this post later.
edit2:
This post contain a makefile with example1.c from Shiru's samples:
viewtopic.php?f=2&t=17467It should work under linux/macos and once compiled, it should create the example and runtime. CC65 needs to be in your path, if not, just update the paths inside the makefile.
Instead of nes.lib, it will create a file called runtime.lib which you should be able to rename to nes.lib and use with alter ego sample.