Other network sims WILL work in the Nexus 4. However, ANY 48 sim card will NOT work with a Nexus 4 as there is an issue with the radio since the android 4.3 update. There is a bug which causes the phone to lose connection, run down the batter, overheat etc when using some 'virtual' networks. There is a fix written but it most likely wont see the light of day until the next major release of Android, which will probably be at the end of October at the very best.
