Yikes. That was literally the first site I even went do back when I got into PC NASCAR games with NASCAR Racing 2 and 3. Used to bring STACKS of floppy disks to my high school computer lab and browse/download tons of schemes to bring home (at the time I was infatuated with Cup driver schemes on the N3 truck expansion). NNRacing was my go-to for sure.
If it's gone (and not something else), IMO, that's tragic.