Once a Nevada mechanics lien has been filed, it will only be valid for a period of 6 months from the date of recording. If you are still within this timeframe a foreclosure action may be brought. One option before filing is to send a Notice of Intent to Foreclose. Consider it a final warning letter sent to the owner and/or GC stating that if you aren't paid you are ready and willing to enforce your rights in court. If not, you should be prepared to file an action in court.
You can find a Nevada construction attorney in your area here.
Good luck!