So Check it out guys my girl brought home a Neuxs 5, and well guess what the problem was... you're right 'No Service' with a SIM in the tray. So I went out and did almost everything possible people had been recommending left and right on different forums, blogs, YouTube vids, etc... you name it. Nothing worked (rarely after doing certain things it would connect but the connection would never stay on the network), untill finally 5-6hrs later I came along some post suggesting hey and if your flashing your radio file be sure to give KRT01B a try, seeing how the poster thought it was a very stable release. So after trying everything I was like !&&* why not, I had even checked the Canadian blacklist at this point and the phone was clean, so I figured !&&* lets try to flash this old ass radio file..... Holy $@$*... The Nexus 5 Connected And Was Holding The Connection, Finally I Can Get Some Sleep.
http://downloads.codefi.re/autoprime/LG/Nexus_5/Modems -> Link To Nexus 5 Radio Files