is avast compitable with nod anti virus
yes, and no…
They won’t mess up each other if you only run 1 resident guard at the time.
This means “Avast resident shield” or “Amon guard from Nod”.
I personally dislike having 2 Av on 1 machine.
I recommend to do a online scan now and then (for backup) with housecall instead :
http://housecall.trendmicro.com/
Waldo
If you want some suggestions for a second backup antivirus:
a) first of all, listen Waldo… He’s the best on these things.
b) take a look here in the section Antivirus tools (not resident; compatible with avast!) 
Wellcome to forums ;D
Nod32 does not like any other AV with it if it is your main AV. It denies access to your files so the other AV can not scan them. :
:
but if you just disabled it and used it as your backup one , it would work just fine… ;D ;D
for me, I use avast as my main AV and Nod32 v.2 as my backup one…
more info…