I didn't say it was definitely ok. This has been discussed here a lot. There is no clear policy on this from USCIS. International law would dictate that an asylee shouldn't use his/her NP, but USCIS seems to be ok with it. Some IOs even encourage you to use/renew your NP. So, it depends on how comfortable you are using it, and how your home country will respond to seeing your GC with an AS category (do they know what it means?). If you can justify your use of your NP, you will be ok.